ˈtesərə noun
( plural tesser·ae -əˌrē, -rī)
Etymology: Latin, perhaps from Greek tessares, tesseres, tettares four; from its being four-cornered — more at four
1.
a. : a small tablet or die (as of wood, bone, or ivory) used by the ancient Romans as a ticket, tally, voucher, or means of identification
tesserae … served as tokens for the distribution of corn — R.L.Poole
b. : an identifying card or password
showed him the tessera with photograph and identification — Ernest Hemingway
2.
a. : a small piece (as of marble, glass, or tile) cut usually with a square or rectangular face and used in mosaic work
inlaid with shining tesserae of blue glass — Norman Douglas
b. : something that is likened to a piece of mosaic
tesserae cemented together with brief comment and explanation — Times Literary Supplement
3. : a small rectangular plate of bone (as in the carapace of the armadillo)