拓扑 (tuòpū) is a phonetic transliteration of 'topology' — picked precisely because the characters can also evoke 'extending' (
拓) and 'broad' (
扑), a faintly suggestive but mostly sound-based loan. Cousin fields:
代数拓扑 (dàishù tuòpū, algebraic topology),
微分拓扑 (wēifēn tuòpū, differential topology).
