Lagging
Pronunciation : Lag"ging
Part of Speech : n.
Definition : 1. (Mach.)
Defn: The clothing (esp., an outer, wooden covering), as of a steam cylinder, applied to prevent the radiation of heat; a covering of lags; -- called also deading and cleading.
2. Lags, collectively; narrow planks extending from one rib to another in the centering of arches.
Source : Webster's Unabridged Dictionary, 1913