A group of four things. / (biology) Two pairs of sister chromatids (a dyad pair) aligned in a certain way and often on the equatorial plane during the meiosis process.

plural of tetrad

Of or relating to a tetrad. / (of a shape) Having four-fold symmetry; used especially of the digits 0, 1 and 8.

(rare, medicine) The tetralogy of Fallot.

fourteen

(anatomy) Having four digits on a limb.

Any animal having four digits on a limb.

a polygon having fourteen sides and fourteen angles

plural of tetradecagon

plural of tetradecane