Is the word said a synonym for plead?

No, "said" and "plead" are not synonyms. They have different meanings and usage.

Said simply means to utter or speak something. For example:

* "She said hello."

* "The teacher said it was time for recess."

Plead has a more specific meaning. It means to:

* Make an earnest request or appeal: "He pleaded with the judge for mercy."

* Present a case in a court of law: "The lawyer pleaded her case passionately."

While "said" can sometimes be used in a context similar to "plead," it doesn't carry the same intensity or formality.