tessera

Definition of Tessera in English :

1. tessera

a small square tile of stone or glass used in making mosaics

WordNet Lexical Database for English. Princeton University. 2010.

Tessera

noun plural -serae (-səˌriː)

1.

a small square tile of stone, glass, etc, used in mosaics

2.

a die, tally, etc, used in classical times, made of bone or wood

nounWord forms: plural ˈtesserˌae (ˈtɛsərˌi ; tesˈərēˌ)

1.

in ancient Rome, a small tablet of wood, ivory, etc. used as a token, ticket, label, etc.

2.

any of the small pieces used in mosaic work

n. pl. tes·ser·ae (tĕsə-rē′)

One of the small squares of stone or glass used in making mosaic patterns.