以便
yǐbiàn · HSK 5
in order to
以 = so as to + 便 = convenient; together: so as to make convenient
以 marks purpose or means (so as to, by means of), and 便 carries the sense of convenience or ease. Combined, 以便 introduces a clause stating the convenient outcome the prior action aims to enable.
以 — phonetic 㠯 (plow/tool) + 人 (person)
Originally a pictograph of a hand-held plow or tool (㠯), later combined with 人 (person) to suggest 'using' something. The core meaning 'to use' extended metaphorically to 'by means of', 'with', and 'because of'. In modern Chinese it functions mainly as a grammatical particle.
便 — person 亻 + change 更
A semantic compound: 亻(person) beside 更 (to change/replace). The original sense was a person making things easier or more convenient by adjusting them. From 'convenient' it extended to 'then/thereupon' (biàn) and to bodily 'discharge' (as in 大便).