BITTY BITS is a term used to refer to very small pieces or amounts of something. It can be used to describe anything from ATOMS to IOTAS. In the context of this crossword, BITTY BITS refers to ATOMS and IOTAS, which are both extremely small particles. ATOMS are the smallest unit of matter that still retains its chemical properties, while IOTAS are the smallest letter in the Greek alphabet. Both ATOMS and IOTAS are so small that they cannot be seen with the naked eye.