slab (n.)youdaoicibaDictYouDict[slab 词源字典]
late 13c., "large, flat mass," of unknown origin, possibly related to Old French escopel, escalpe "thin fragment of wood," which according to Klein is possibly a Gaulish word (compare Breton scolp, Welsh ysgolp "splinter, chip"). But OED rejects this on formal grounds. Meaning "rectangular block of pre-cast concrete used in building" is from 1927. Slab-sided is "having flat sides like slabs," hence "tall and lank" (1817, American English).[slab etymology, slab origin, 英语词源]