時刻
じこく · jikoku · JLPT N3 · noun
hour
⏰ 時刻 = time (時) + carve (刻): a moment carved out of time
時 is time in general; 刻 means to carve or notch. Old water clocks had notches marking each interval, so 時刻 is one exact notch of time: a specific clock time, as in 時刻表 (jikokuhyō), a timetable.
刻 — knife radical 刂 + 亥 (phonetic)
A semantic-phonetic compound. The right side 亥 supplies the sound, while the knife radical 刂 on the right gives the meaning, since 刻 originally referred to carving or engraving with a blade. From 'to carve' it extended to marking time notches on a sundial, hence the modern sense of 'a moment' or 'quarter hour'.