PIE base ‘to fold’. See also *plek- ‘to plait, fold’.
Derivatives include fold, twofold, multiple, and haploid, literally ‘one-folded form’, from Greek haploos, haplous ‘single, simple’, but not diploid, literally ‘double form’, from Greek eidos ‘act of seeing, form; idea’, from PIE root *weid- ‘to see’.
[Pokorny *pel-3a, pp. 802–803]
Glossary terms for this common ancestor to be added.