Meanings

old dog

go-between

progeria (disease characterized by symptoms suggestive of premature aging)

anti-aging

old folks' home

old folks' home

deterioration

old woman

study hard while you are young

lobster

kanji "old" radical at top

helmet with white hair coming out of the top, making the wearer look like an old person

freshwater prawn (Macrobrachium spp., esp. the Oriental river prawn, Macrobrachium nipponense)

sakura shrimp (Lucensosergia lucens)

giant tiger prawn (Penaeus monodon)

Council of Five Elders

gammaridean amphipod (any small, shrimp-like crustacean of suborder Gammaridea)

Yōrō Code (promulgated 757 CE)

(both) young and old

banded coral shrimp (Stenopus hispidus)