TANTAMOUNT a. 2 definitions
Equivalent in value, signification, or effect. A usage nearly tantamount to constitutional right. Hallam. The certainty that delay, under these circumstances, was tantamount to ruin. De Quincey.
ABERRATION n.
the earth in its orbit, and dairy or diurnal aberration, when of the earth on its axis; amounting when greatest, in the former case, to 20.4'', and in the latter, to 0.3''. Planetary aberration is that due to the motion of light and the motion of the planet relative to the earth.