Moths and butterflies are grouped together in the order Lepidoptera, which means 'scaly wings'.
Moths in comparison to Butterflies:
Moths are active during the night vs. butterflies are active during the day.
Moths have featherlike antennae vs. butterflies have clubbed antennae.
Moths connect their wings with a fringe called a frenulum vs. butterflies don't.
Moths usually rest with their wings tented down their back vs. butterflies rest with their wings folded.