the.com/capitalization

means The act of converting an asset's expected future earnings into a present-day value, or more simply, writing a word with its first letter in uppercase.

from From Latin 'caput' meaning 'head' — the same root that gives us 'capital' and 'captain.' The financial sense comes through 'capital' as in a sum of principal money, so 'capitalize' meant to convert something into capital, i.e., a lump-sum asset. The spelling sense (capital letters) traces the same root differently: Roman inscriptions used large letters atop columns called 'capitals' — literally the 'head' of the column — and that architectural term lent its name to the big letters themselves.