twain
Pronunciation: /tweɪn/
cardinal number
- archaic term for two. he split the spar in twain

Phrases
-
never the twain shall meet
- used to suggest that two things are too different to exist alongside each other: families were either ‘church’ or ‘chapel’ and never the twain shall meet[from Rudyard Kipling's ‘Oh, East is East, and West is West, and never the twain shall meet’ (Barrack-room Ballads, 1892)]

Origin:
Old English twegen, masculine of twā (see two)