| Subject | English | Japanese |
| gen. | proto cell | 前細胞 |
| tech. | proto-Doric order | プロト•ドリス式オーダー (プロト•ドリスしきオーダー) |
| gen. | n Proto-Indo-European | インドヨーロッパ祖語 (hypothetical language from which all Indo-European languages are derived) |
| gen. | n adj-no Proto-Indo-European | 印欧基語 (hypothetical language from which all Indo-European languages are derived) |
| gen. | n Proto-Indo-European | 印欧祖語 (hypothetical language from which all Indo-European languages are derived) |
| gen. | n Proto-Indo-European | インド・ヨーロッパ祖語 (hypothetical language from which all Indo-European languages are derived) |
| gen. | n proto-Sinaitic script | シナイ文字 |