'Thank offerings' in the Bible

Then Hezekiah answered and said, Now ye have consecrated yourselves to the LORD, come near and bring sacrifices and thank-offerings into the house of the LORD. And the congregation brought in sacrifices and thank-offerings; and, as many as were of a free heart, burnt-offerings.

And he repaired the altar of the LORD, and sacrificed on it peace-offerings and thank-offerings, and commanded Judah to serve the LORD God of Israel.