(astronomy) the particular appearance of a body's state of illumination (especially one of the recurring shapes of the part of Earth's moon that is illuminated by the sun) | the phase of the menstrual cycle during which the lining of the uterus is shed (the first day of menstrual flow is considered day 1 of the menstrual cycle) |
(physical chemistry) a distinct state of matter in a system; matter that is identical in chemical composition and physical state and separated from other material by the phase boundary | |
any distinct time period in a sequence of events | |
a particular point in the time of a cycle; measured from some arbitrary zero and expressed as an angle | |