皓 is a bound morpheme — it doesn't stand alone. Common compounds: 皓月 (bright moon), 皓齿 (white teeth), 皓首 (white-haired, i.e. old age). Famous in Fan Zhongyan's 《岳阳楼记》: 皓月千里 (the bright moon shining a thousand li).
memory
皓 = 白 (white) + 告 (gào, phonetic). Picture announcing (告) something white (白) — the moon, teeth, or aged hair. The 白 component is your meaning anchor.
