The word waxing refers to the application of wax on something. This would cause the thing to grow in girth, or to appear to, as the layers of wax thicken. Most often when we witches use the word waxing, we are referring to the waxing phase of the moon. This is the phase when the moon appears to be growing, or thickening, from the period of the new moon to the period of the full moon.
Magickally, the waxing moon period is considered the best for magick and mundane actions related to growing, drawing, creating, increasing and protection.