Circadian organization is the rules and principles that guide the entire circadian system from the cells up. Circadian organization does not refer to activities within a cell, but how cells work together to be rhythmic. If circadian rhythms were a house, circadian organization would be the blueprints. This term is reserved for living organisms. Daily activity rhythm is another term for a circadian rhythm.
Circadian oscillators are biological clocks.
Circannual is an annual rhythm. An example would be the annual migration of monarch butterflies from North America to Mexico. A clock is a term to describe the entire biological mechanism that regulates natural occurring rhythms in an organism. This mechanism occurs in a particular gene referred to as a clock gene. There are different clocks for different rhythms.