shelter

The story

1. Old English · inherited fromsċildtruma
2. Middle English · inherited fromsheltron
3. English todayshelter

From Middle English sheltron, sheldtrume (“roof or wall formed by locked shields”), from Old English sċildtruma, sċyldtruma (“a phalanx, company (of troops), a tortoise, a covering, shed, shelter”, literally “shield-troop”), from sċyld, sċield (“shield”) + truma (“a troop of soldiers”). Cognate with Scots schilthrum, schiltrum. More at shield, and Old English trymman (“to strengthen”), from trum (“strong, firm”) at trim. Doublet of sheltron (a kind of military formation), which is the more conservative of the two.