convalesce (v.) Look up convalesce at Dictionary.com
late 15c., from Latin convalescere "thrive, regain health," from com-, intensive prefix (see com-), + valescere "to begin to grow strong," inchoative of valere "to be strong" (from PIE root *wal- "to be strong"). Only in Caxton and Scottish writers until 19c. Related: Convalesced; convalescing.