Seilfaen, n. foundation stone
Seiliant, n. a foundation
Seilio, v. to lay a foundation
Seiliog, a. having a foundation
Seilwaith, n. ground-work
Seilydd, n. a founder
Seimio, v. to grease over
Seimiol, a. of a greasy quality
Seimlyd, a. of a greasy quality
Seinfawr, a. sonorous, loud