二日
ふつか · futsuka · JLPT N5 · noun
days
📅 futsu-ka = old native futa (two) + ka (day), not ni + nichi
二日 uses the old native Japanese count: futa (two, as in futatsu) plus ka, the native counter for days. Futa-ka slurred into futsuka. The same ka ends mikka (3rd), yokka (4th) and tōka (10th).
二 — two horizontal strokes 一 + 一
二 is an indicative character showing the number two with two simple horizontal lines, parallel to 一 (one) and 三 (three). The form has been stable since oracle bone script. It directly represents the concept of 'two' rather than depicting any physical object.
日 — pictograph of the sun
日 is a pictograph of the sun, originally drawn as a circle with a dot or stroke inside representing the sun's substance. Over time the round shape was squared off into the modern rectangular form. It means 'sun' and by extension 'day'.