A system of grammatical gender, whereby every noun was treated as either masculine, feminine or neuter, existed in Old English, but fell out of use during the Middle English period. Modern English retains features relating to natural gender, namely the use of certain nouns and pronouns (such as "he" and "she") to refer specifically to persons or animals of one or other genders and certain others (such as "it") for sexless objects – although feminine pronouns are sometimes used when referring to ships (and more uncommonly some airplanes and analogous machinery) and nation-states.