From PIE *dwoh₁ — one of the most stable words across all Indo-European languages, hidden in 'twin' and 'doubt.'
The cardinal number equivalent to the sum of one and one; the second positive integer.
From Old English 'twā' (feminine and neuter; the masculine was 'twēgen'), from Proto-Germanic *twō, from PIE *dwóh₁ meaning 'two.' This is one of the most stable words in all Indo-European languages, virtually unchanged in meaning for over six thousand years. The same root produced Latin 'duo,' Greek 'dúo,'