in'terval

[L. inter, between, vallum, wall.] time or space between two periods or objects; a break in a current or the course of a disease; a period of rest between two of activity. a.-c. i., auriculocarot'id i., atriocaxot'id i., the time between the beginning of the auricular and that of the carotid waves in a tracing of the jugular pulse; the inter systolic period, c.-a. i., cardioarte'rial i., the time between the apex beat of the heart and the radial pulse beat, pa ive i., the period of rest of the heart, presphyg'mic i. [L. pr(B, before, + ginning of the ventricvdar systole during which the pre ure is rising before the semilunar valves open.