Monier-Williams: A Sanskrit-English Dictionary (p. 4)
aguru, mfn. not heavy, light; (in prosody) short as a short vowel alone or before a single consonant; (us, u), m.n. the fragrant Aloe wood and tree, Aquilaria agallocha.

Monier-Williams: A Sanskrit-English Dictionary (p. 307)
kṛṣṇāgarukāṣṭha, n. a black variety of Aloe wood, Gal.; kṛṣṇāguru, n. id., Kād.; -maya, mfn. made of that Aloe wood, Hcat.

Tamil Lexicon, University of Madras (p. 14)
akaru: Eagle-wood, l. tr., Aquitaria agallocha

Tamil Lexicon, University of Madras (p. 17)
akil: 1. Eagle-wood, l. tr., Aquitaria agallocha; 2. The drug agar obtained from the trunk and branches of eagle-wood when they become gorged with a dark resinous aromatic juice, one of six tūpa-varkkam; 3. Blinding-tree; 4. Chittagong wood, l. tr., Chickrassia tabularis

Dymock, Warden, Hooper: Pharmacographia Indica (vol. III, pp. 217-221)
Aquilaria agallocha, Aquilaria malaccensis, Thymelaeaceae
The use of this precious wood as a perfume and medicine is of great antiquity, together with myrrh, cassia, and other products of the East, it is mentioned in the sacred writings of the Jews (Num. 24, 6; Psalm. 45, 8; Prov. 7, 17; Cantic. 4, 14) under the name of Ahalot or Ahalim. It is the -*- of the ancient Greeks, which is described by Dioscorides as a wood brought from India to Arabia. Later writers, from A‰tius' time, call it -*- or "aloe wood", the name by which it is still known in Europe. The same substance is the Agaru of the Hindus, the Garu of the Malays, and the Chin-heang of the Chinese. In Sanskrit medical works it bears the synonym of Rājārha "worthy of prince," Visvarūpa "taking all forms," Krimi-ja "produced by worms," Krimi-jagdha, Anarya-ja "produced in a non-Aryan country," Kanaka "golden," Kāliya "black," &c., and is described as hot, light and cholagogue; removing diseases of the ear, nose and eyes. In native practice Agar is used as a deobstruent, stimulant, carminative, and tonic; it is said to relieve the pain in gout, and to check vomiting. Suśruta directs Aguru, Guggula (resin of Boswelia serrata), Sarjarasa (resin of Shorea robusta), Vacha (Acorus Calamus), white mustard, Nim leaves and salt to be made into a paste with ghī to form an anodyne fumigation for surgical wounds, called in Sanskrit Vedanārakshoghnairdhupaih. As aloe wood bears the Sanskrit name of Anarya-ja, it is probable that it was used by the aborigines of Eastern Asia before it became known to the Hindus, but that at a very early date it was carried overland to Central Asia and Persia, and from thence reached Arabia and Europe.
The early Arab travellers appear to have collected a good deal of information concerning the commerce and sources of supply of the wood. Yohanna-bin-Serapion mentions four kinds, Hindi, Mandali, Sinfi and Kamāri, and Ibn Sina in the 10th century has the following account of it: -"The best is called Mandali from the more central parts of India; next is the Indian or Hill aloe wood, which has the advantage over Mandali of preserving clothes from lice. Some say that Mandali and Indian aloe wood are the same. One of the best kinds is Samandōri from Sofala in India; again there is the Kamāri and the Simfi from the same parts, and there is Kākuli, and Kismōri which is moist and sweet; and the worst kinds are Halāi, Kamtāi, Mabatāi, Lawathi, or Rabatāthi. Mandali is the best; then Samandōri, of a grey colour, fat and oily, heavy, without any white streaks, and which burns slowly. Some consider black aloe wood better than grey, and the best black is the Kamāri, without white streaks, fat and oily, which burns slowly. In short, the best aloe wood is black, hard, and heavy, sinks in water, is not fibrous when powdered; that which does not sink is bad. The tree is said to be buried to promote the formation of aloe wood." The Arabian travellers give much the same names to different kinds of the wood. Ibn Batuta speaks of Kamāri as soft, like wax. Abu Zaid calls it Kamarōni, and says it is the best kind. Abulfeda states that it comes from the Kamarōn Mountains. Kākuli is said to derive its name from Kākaleh in Java. The epithets Māwardi, Saimuri and Jāwi are also applied by some writers to aloe wood. As regards the identification of these localities, we would remark that Samfi is probably derived from Champa, a province in Cambodia; Mandali, from Mount Mandar or Mandal, south of the modern town of Bhagalpur in Bengal; Kāmari or Kamaruni, from Kamarun, the Arab name for Cape Comorin; Saimōri, from Saimōr or Samar, an island in the Eastern Archipelago; Halāi may possibly be derived from the Hala Mountains between Sind and Beluchistan, as Abu Zaid says that the best aloe wood is brought for sale by Multanis.
Haji Zein-el-Attār (1368) calls aloe wood Ood-el-jāj, and in Persian, Ood and Balanjōj. After translating Ibn Sina's article on Ood, he gives his own opinion in the following terms: "The author of this work (Ikhtiarat-i-badiaa) says the best is called Kalambak, and comes from the port of Jena, which is ten days' sail from Java; it is sold for its weight in gold; you would think it odourless, but when warmed in the hand it has a very sweet persistent odour; when burnt, the odour is uniformly sweet until the wood is consumed. Next is Mandali and Samandōri, both from Sofala in India, the best of these is of a golden colour and heavy. Kākuli is like the Indian, and is generally in large pieces, marked with black and yellow lines; then there is Kamāri, golden-brown, without white streaks, it comes from Kamarōn and Sofala; then Samfi, from Samp, it is very hard and sweet; then Sakāli and Afasi, a moist kind from China; then Mantai, Randi, Halai, and Lanfi, all of about equal value. And in Manta there is a tribe who call the wood Ashbāh, and it is of two kinds: one of these is in large pieces weighing from 5 to 50 maunds, without much odour, and used for making combs, knife handles, &c.
Mir Muhammad Husain (1770) writes: -"Ood, in Hindi Agar, is the wood of a tree which grows in the Jaintiya hills near Sylhet, a dependency of the Sōbah of Bengal, situated towards the north-east of Bengal Proper. The tree is also found in the islands to the south of Bengal, situated north of the Equator, and in the Chatian islands belonging to the town of Nawaka, near the boundaries of China. The tree is very large, the stem and branches generally crooked, the wood soft. From the wood are manufactured walking sticks, cups, and other vessels; it is liable to decay, and the diseased part then becomes infiltrated with an odoriferous secretion. In order to expedite this change it is often buried in wet ground. Parts which have undergone the change above mentioned become oily, heavy and black. They are cut out and tested by being thrown into water; those which sink are called Gharki, those which partly sink Nim Charki, or Samāleh-i-aala, and those which float Samāleh; the last kind is much the most common. Gharki is of a black colour, and the other qualities dark and light-brown."
The best kind for medicinal use is Gharki Ood from Sylhet; it should be bitter, odoriferous, oily and a little astringent; other kinds are considered inferior. In most receipts raw Ood (Ood-i-khām) is enjoined to be used to prevent the use of wood from which the oil has been abstracted by crushing and maceration in water, or by crushing and admixture with almonds, which are afterward expressed (Nicolaus Myrepsicus prescribes Agallochum crudum). This precaution is the more necessary as Ood shavings are an article of commerce in India under the name of Chōra agar; they are often adulterated with chips of Sandalwood, or Taggar, an odoriferous wood, common in India.
Rumphius describes two kinds of true, and two of false, aloe wood; the first kind of true aloe wood, he says, is called Kilam or Ho-Kilam by the Chinese, and Calambac by the Malayas, and is produced by a tree growing in the provinces of Champa and Coinam, and in Cochin-China. This tree has been described by Loureiro under the name Aleoxylon agallochum. The second kind, called Garo, is the product of Aquilaria malaccensis, Lamk. which he figures. This is the Chin-heang of the Pun-tsaou-kang-muh or great Chinese Herbal. (See Hanbury Science Papers, p.263.) His two kinds of false aloe wood he attributes to Michelia champaca and Excoecaria agallocha.
Roxburgh and other botanists have examined the Aquilaria in Sylhet, and recently an Aquilaria has been ascertained to be the tree which produces aloe wood in the islands of the Mergui Archipelago. Gamble says that "Akyu (the Burmese name for aloe wood) is the most important produce of the forests of South Tenasserim and the Mergui Archipelago. It is found in fragments of various shapes and sizes in the centre of the tree, and usually, if not always, where some former injury has been received."
Aloe wood is used throughout the East as an incense and as a perfume, and was formerly used as a medicine in Europe for the same diseases for which it is still prescribed in India.
Collection. -In Sylhet, the collection of aloe wood is a precarious and tedious business; those engaged in it proceed some days' journey into the hilly districts, where they fell any trees they may find, young or old, and then, on the spot, search them for the Agar, as the valued wood is called. This is done by chopping off the bark, and into the wood, until they observe dark coloured veins, indicating the proximity of wood of valuable quality, which generally extends but a short distance from the centre of a trunk or branch. In this manner a whole tree is searched through, the collectors carrying away only such pieces as are rich in odoriferous resinous matter. In some districts it is customary to facilitate the extraction of the resinous wood by burying portions of the tree in moist ground, or by allowing the entire tree to remain a length of time after it is cut down, the effect of which is to cause decay in the non-resinous wood, and thus render it easily removable by an iron instrument. Aloe wood is sorted by the collectors into various qualities, the finest of which, called Charki, is worth in Sylhet from 6 to 8 rupees per pound. (Hanbury Science Papers.)