For those wanting to know what the new Snapchat emoji symbols mean, there is several different things that they repersent and these emojis have replaced the âBest Friendsâ feature with Friend Emojis smilies.
(plural tetrads) 1  A group of four things. ( 2 chemistry) A tetravalent atom or radical. ( biology) Two pairs of sister chromatids (a dyad pair) aligned in a certain way and often on the equatorial plane during the meiosis process.
Webster Dictionary(0.00 / 0 votes)Rate this definition: 1  Tetrad(noun) the number four; a collection of four things; a quaternion. 2  Tetrad(noun) a tetravalent or quadrivalent atom or radical; as, carbon is a tetrad.