I was reading this particular sentence:
She took the disguise of an old woman and came to Eleusis, where she was welcomed by the family of King Celeus.
Disguise means costume. So, does it mean she took an old lady's clothes?
No! The verb take has various uses and senses. She took the clothes of an old woman would have the sense you mean, but take is not infrequently used 'delexically' - as a sort of 'dummy', bleached-of-semantic-content verb; the expressions where this happens are really fixed idioms. Examples are:
But note that the delexical - lexical distinction can get blurry:
Sauron took the form of a mighty warrior clothed in armour.
Here, 'take the form' implies an electing to exist in this form at this time, so take is not just a verb bleached of meaning here. This is true also with 'take the disguise (of)'.