to grow old: to advance in years and become aged
This verb describes a living being reaching old age. It is the ordinary word for a person becoming or being far along in years, and the Bible uses it of Abraham, Sarah, Isaac, Joshua, Eli, Samuel, David, and others as they reach the end of a long life. It can also stretch to non-human life, as when a tree stump grows old in the ground.
In story after story the plain statement "he was old" or "she had grown old" does more than report an age. It marks a turning point: a life is nearly complete, and questions of blessing, inheritance, succession, and who will carry on now come to the front. So the word often carries the weight of a whole life reaching its final stage, even though it means simply to grow old.
The same three consonants spell two other closely related words: a noun for an old man or a community elder, and a word for the beard that marks a grown man. They all cluster around the idea of age and the standing that comes with it, but this entry is the verb, the act of growing old itself.