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Webster 1913 Edition

Semidiurnal

Semˊi-di-ur′nal

,

Adj.

1.

Pertaining to, or accomplished in, half a day, or twelve hours; occurring twice every day.

2.

Pertaining to, or traversed in, six hours, or in half the time between the rising and setting of a heavenly body;

as, a

semidiurnal

arc

.