Absolute reference
Galilean reference frame (without acceleration).
Admittance
The ocean's response, depending on the frequency, to the action of the generating force.
Age of the tide
Time interval between the syzygy and the maximum range of tide that follows.
Altimetry
Measurement of the height of water using spatial techniques.
Amphidromic points
Points located at sea around which the tide wave appears to turn.
Amplitude
Difference between the height of a high or low tide and the mean level. This term is often used in error to designate the range of tide.
Apparent time
True solar hour angle.
Argument number
Method for designating the components of the tide, using a 6-figure number, making it possible to identify the astronomical parameters from which they are derived and deduce from them their period.
Ascending node
Point at which the lunar orbit and the ecliptic intersect in the direction of movement of the Moon from the Southern to the Northern hemisphere.