Wherewithal comes from where + withal ('with'), originally a conjunction/adverb meaning 'with which', later nominalized to mean the means or resources needed for a purpose. In current use it is a noun meaning "the money, means, or resources needed for a purpose". That sense is explained by the older material without requiring a speculative semantic step: the inherited or borrowed base supplies the field of meaning, while the English formation fixes its modern role. The surface form is compositional: its joined elements remain visible in the modern word. The historical chain includes Old English hwǣr and Old English wiþ eallum. Related English forms include wherewith and where. The semantic development is therefore important as well as the form: the word moves from the older concrete, technical, or literal setting into the present figurative or specialized sense.