This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

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adj. Of, relating to, or concerned with the stars or constellations; stellar.

adj. Measured or determined by means of the apparent daily motion of the stars: sidereal time.

adj. Of or relating to the stars.

adj. Relating to a measurement of time relative to the position of the stars.

adj. Relating to a measurement of time relative to the point of the vernal equinox.

adj. Relating to the stars; starry; astral.

adj. Measuring by the apparent motion of the stars; designated, marked out, or accompanied, by a return to the same position in respect to the stars

Pertaining or relating to the constellations or fixed stars; consisting of or constituted by fixed stars: as, the sidereal regions; sidereal calculations; a sidereal group or system.

adj. of or relating to the stars or constellations

adj. (of divisions of time) determined by daily motion of the stars

"This is the difference between what we call the sidereal day (the time that it takes to make one complete rotation) and the synodic day (the time that it takes to go from the Sun highest in the sky until the Sun is again at its highest in the sky)."

sidereal time    sidereal year    sidereal day    sidereal clock    sidereal magnetism    sidereal system   

sidereal clock    sidereal day    sidereal month    sidereal hour    sidereal astrology   

starry    astral    Starr   

sider   

Ptolemaic    Copernican    be-all    pseudo-random    stellar    Newtonian    einsteinian    warp-field    space-based    unreckonable