Sure. It means to expose the plant to sunlight gradually. Right now, though, it is too early to put them outside. I probably wouldn't try until early May. If it starts to really get warm there, above 70, then you can try taking them outside on the porch for a few hours. Once it warms up, mid-May, then you can leave them outdoors on the porch, and start to expose them to direct direct sunlight, starting with 30 - 60 minutes then gradually increasing the time over 7 - 10 days. If you see leaf burn, take them back into shade.

Thanks a lot - that's just what I will do.