Provenance
Where it comes from.
'Build' goes back to late Old English byldan, 'to construct a house,' from bold, 'a dwelling,' and a Germanic root tied to the idea of dwelling and growing. Figurative senses, such as building up a reputation or a fortune, were in use by the mid-1400s.
'Root' comes from late Old English rot and Old Norse rot, 'the underground part of a plant,' with a figurative 'source or origin' sense recorded from the late 1100s. 'Take root,' meaning to settle and become established, follows in the 1400s. Between them the words move from foundation to growth in a single breath.