This is the verse translation, not a definition of the individual word.
It is He Who created the heavens and earth for a true purpose. On the Day [of Resurrection] He will say, “Be,” and it will be. His word is the truth. His is the dominion on the Day the Trumpet will be blown. He is the Knower of the unseen and the seen, and He is the All-Wise, the All-Aware.”