Striated means marked with narrow lines, stripes, or bands — often lines of different colour, or thin grooves you can feel with a finger. It is a formal, technical word. Geologists use it for rock scratched into parallel lines by a moving glacier; biologists use it for 'striated muscle', the kind of muscle that looks striped under a microscope and that you can move on purpose (your arm), as opposed to smooth muscle (your stomach wall). It also appears when describing minerals, shells, leaves, and sometimes cloud or sand patterns. In ordinary conversation English speakers would just say 'striped' or 'lined'; striated belongs to science writing, museum labels, and medical texts. It works as an adjective, and there is a rare verb 'striate' behind it.