age
齢 centers on the concept of age, specifically the number of years a person or living thing has lived.
齢 is the modern Japanese simplified form of 齡. The older form combines 齒 (teeth) with 令, which likely contributes the sound. Teeth were traditionally used to estimate age in animals, giving the character its meaning.
The left side 歯 means teeth, and the right side 令 looks like a person kneeling under a roof. Imagine checking a horse's teeth to determine its age—the longer the teeth, the older the horse.
For レイ, picture a ray of light shining on an old person's teeth, revealing their age: ray -> レイ.
age; years
advanced age; old age
(one's) age
age of a tree
old age; advanced age
suitable age
age of the Moon; number of days since the new moon
school age
young (usu. of a woman); blooming; in the prime of youth; marriageable
(one's own) age
housing for the elderly with home-care services provided
middle and advanced age
young (e.g. young children); of few years
age lowering; reduction in age
biological age of the body (based on fitness metrics); body age
life expectancy
young old (person between 65 and 74 years old)
aging; ageing; growing older
age-related; aging-associated
age-related cataract