
1) Abaciscus 2) Mosaic tile
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https://www.crosswordclues.com/clue/abaculus

small tile for mosaic
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http://phrontistery.info/a.html

• (n.) A small tile of glass, marble, or other substance, of various colors, used in making ornamental patterns in mosaic pavements.
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http://thinkexist.com/dictionary/meaning/abaculus/
A·bac'u·lus (ȧb*ăk'u*lŭs)
noun ;
plural Abaculi (-lī). [ Latin , dim. of
abacus .]
(Architecture) A small tile of glass, marble, or other substance, of various colors, used in making ornamental patterns in mosaic pavements.
Fairholt....
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http://www.encyclo.co.uk/webster/A/1

In architecture, an abaculus is a small tile of glass, marble, or other substance, of various colours, used in making ornamental patterns in mosaic pavements.
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http://www.probertencyclopaedia.com/browse/TA.HTM

abaculus A small tile used in mosaics.
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http://www.wordinfo.info/words/index/info/view_unit/2220/

abaciscus.
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https://www.infoplease.com/dictionary/abaculus
No exact match found.