1. To extend or stretch to or in the direction of someone or something in a higher position. I reached up to Jake so I could grab the hammer from him. My eyes reached up to the sky through my grandmother's telephone. The flower opened its petals and reached up to the morning sunlight.

2. To extend or stretch something to or in the direction of someone or something in a higher position. In this usage, a noun or pronoun can be used between "reach" and "up to." I reached my hand up to Sarah so she could pull me out of the ditch. I reached the hammer up to Jake so he could finish the work on the roof.