Pl. tesseræ. [L., f. Ionic Gr. τέσσερες, -ρα, = Attic τέσσαρες, -ρα four.]
1. Anc. Hist. A small quadrilateral tablet of wood, bone, ivory, or the like, used for various purposes, as a token, tally, ticket, label, etc.
Tessera of hospitality (= L. tessera hospitalis), a die broken between host and guest, and kept as a means of recognition.
1656. Blount, Glossogr., Tessera, a thing in every part square as a dye; also a watchword, or signal, a note, mark or token, &c.
1846. Keightley, Notes Virg., Georg., II. 508. In the ancient theatres … each spectator’s tessera designated the cuneus and row in which he was to sit.
1850. Leitch, trans. C. O. Müller’s Anc. Art, § 412 (ed. 2), 569. One brings him a tessera of hospitality from Sisyphus.
1886. Guide Exhib. Galleries Brit. Mus., 186. Objects in bone and ivory, such as caskets, gladiatorial tesseræ, tickets for the theatre, dice.
b. fig. A distinguishing sign or token; a watch-word, a password. (The earliest use in English.)
1647. Jer. Taylor, Lib. Proph., i. 17. That Creed made so explicite as a tessera of a Christian.
1656. [see prec.].
1662. Owen, Animadv. Fiat Lux, ii. Wks. 1855, XIV. 29. Making subjection to the pope in all things the tessera and rule of all church communion.
1795. in Calderwood, Dying Testimonies (1806), 460. Exacts it from them as a tessera of their loyalty.
1890. Hatch, Hibbert Lect., xii. 344. It was, so to speak, a tessera or password.
2. spec. Each of the small square (usually cubical) pieces of marble, glass, tile, etc., of which a mosaic pavement or the like is composed. Usually in pl.
1797. S. Lysons, Rom. Antiq. Woodchester, 4. The tesseræ of which this [mosaic] pavement is composed, are, for the most part, nearly cubes of half an inch…. Many are triangular, and of various other shapes.
1843. Civil Eng. & Arch. Jrnl., VI. 125/1. The next point to be observed with reference to the Roman tesseræ, is the want of uniformity in their size and shape.
1894. Times, 5 March, 14/1. The workmen had to learn to set the tesseræ, one by one and each in its proper place, into the cement on the wall.
b. transf. Any one of the quadrilateral divisions into which a surface is divided by intersecting lines; e.g., by the lines of latitude and longitude.
1873. Maxwell, Electr. & Magn. (1881), I. 198. So that the spherical surface is divided into quadrilaterals or tesseræ … bounded by meridian circles and parallels of latitude.
c. Zool. Each of the plates of which the carapace of an armadillo is composed.
1909. in Cent. Dict., Suppl.
† 3. (See quots.) Obs.
1815. J. Smith, Panorama Sc. & Art, I. 257. John’s tessera is perhaps the best of those artificial compositions which are designed for roofing.
1842–76. Gwilt, Archit., Gloss., Tessera … this name was … applied to a composition used some years ago for covering flat roofs, but now … quite abandoned.
