The evenly curved line or circle segment is one of the five
elements of Western ideography.
The structure , the even curve that is a half circle, or a little less, appears in a dozen or so different ideographic systems ranging from modern logic to astrology. In the astrological system of symbols stands for the assimilating, receptive aspect of man that the spirit, life, , creates in its interplay with matter, .
This use of the sign is exemplified in the planet symbol .
In those instances where and appear between other signs they often mean that the ideas represented by those other signs (or those signs themselves) should be merged or should be brought together. In logic the expression a $\cup$ b means the sum of everything contained in a and b. In proofreading, the sign denotes lessen space between signs. Used in musical notation, means legato, to bring notes covered together in one pitch or through slurring to form a whole. In biology it means climbing plant. In one system stands for the faculty of reason, sense, and its double, , stands for the conscience, the higher reason.
When this sign is curved downward, , it often represents a boat. In the Swedish and French systems of hobo signs it denotes a place for sleeping.
is occasionally used to mean the sky, and in some meteorological contexts it can mean rainbow. In early chemistry could mean phosphorus, as could .
Compare with in Group 8 and in Group 14.