Q

quality - the texture of a musical note, whether it is harsh or smooth to listen to
quantised - existing only in discrete units or quanta
quantity - an amount e.g. 1 kg
quantity - a descriptive measurement e.g. length
quantum - a step in energy, a packet of energy
quantum theory - physics of the very small, energy steps, reduces to classical physics at large scale
quark - fundamental particle with charge either -1/3e or +2/3e. Three make up a proton.
quasar - a distant and intense source of radiation. Size of a star, energy of a galaxy!