Meanings

eight parts of speech (in traditional English grammar, etc.)

octave device

regular octahedron

tesseract

eighth brain nerve

single-tiered gate with eight secondary pillars supporting the four main central pillars

octant (instrument)

style of sword fighting

Cyathea mertensiana (species of tree fern)

fairy pitta (Pitta nympha)

large hanging paper lantern (used in bathhouses, yose theatres, izakaya, etc.)

large hanging paper lantern (used in bathhouses, yose theatres, izakaya, etc.)

octennial

sea lamprey (Petromyzon marinus)

the eight gods who preside over the lucky/unlucky directions of the traditional calendar for each year (in Onmyōdō)

49th, 51st, 52nd, 54th, 56th, 57th, 58th or 60th day of the sexagenary cycle (said to be inauspicious with a high probability of rain)

eighth of nine traditional astrological signs (corresponding to Saturn and north-east)

division of the Buddha's 50-year teachings into five time periods and eight categories (theory of the Tendai sect)

eighteen centers of Buddhist learning (of the Pure Land sect in the Kanto region)

thick clouds