光学 (こうがく) — optics

光こう学がく optics

Frequency #7684 Frequency rank among common Japanese words. Lower number = more common. Grade 2 Japanese school grade level in which this kanji is taught. Grade 1 is first year of elementary school. 2 characters 漢語 kango 漢語 (kango) — Sino-Japanese compound: all kanji use on'yomi (Chinese-derived) readings. noun Part of speech (JMdict: n)

kougaku

Pitch高低アクセント — Tokyo-dialect pitch accent. The number is the drop position: 0 = heiban (no drop), 1 = atamadaka (drops after 1st mora), N = drops after Nth mora. The line above each mora marks high pitch; below, low. こうがく[0] heiban 平板

Synth audio is approximate — the diagram is the canonical reference.