| English | Part of Speech | Gaelic |
|---|---|---|
| calcium | n(m) | cailsium |
| calcium carbonate | n(m) | cailsium carbonat |
| carbohydrate | n(m) | carbohaidhdreat |
| carbonate | n(m) | carbonat |
| card | n(f) | cairt |
| centilitre | n(m) | ceudaliotair |
| centilitre | ceudaliotair | |
| centimetre | ceudameatair | |
| challenge cards | cairtean-dùbhlain | |
| chloride | n(m) | clòraid |
| chlorophyll | n(m) | clòrofail |
| chloroplast | n(m) | clòroplast |
| code | n(m) | còd |
| coin | n(m) | bonn |
| column | n(m) | colbh |
| commutative | adj | co-iomlaideach |
| comparison | n(m) | coimeas |
| compasses | cearcallaiche | |
| complementary | adj | co-phàirteach |
| composite | adj | ceangailte |
| composite shape | cumadh ceangailte | |
| compound | n(m) | co-thàthadh |
| concave | adj | fo-chearclach |
| concentric | adj | co-mheadhanach |
| concept | n(m) | bun-bheachd |
| cone | n(m) | còn |
| cone | poss c | còna |
| congruence | n(f) | co-chòrdachd |
| congruent | adj | co-chòrdach |
| connection card | cairt-ceangail | |
| consumer (food chain) | n(m) | caitheadair |
| convection | n(f) | cuartachadh |
| convection current | n(m) | sruth cuartachaidh |
| convex | adj | os-cearclach |
| coordinate | n(m) | co-chomharra |
| corresponding | adj | co-fhreagarrach |
| cost | cosgais | |
| cost | cosgais | |
| cost | cosgais | |
| cotyledon | n(m) | cotyledon |
| cube | n(m) | ciùb |
| cube | vb | ciùb |
| cubed | adj | ciùbaichte |
| cubic | adj | ciùbach |
| cuboid | n(f) | ciùbaid |
| cuboids | pl | ciùbaidean |
| cytoplasm | n(m) | saidhteoplasm |