
When we talk about โCheersโ here we are talking about the clanking together of glasses full of drink. Usually an alcoholic drink.
As usual, this old ritual has no finite definition nor origin. But, there are 3 leading theories on why we โCheersโ. Our favorite reason is simply because itโs fun. Hereโs a little more etymology for ya:

THE ORIGINS OF THE โCHEERSโ:
1. When you drink, you look, smell, feel, taste, but you do not hear the drink. When you click glasses together, you gain the sound of the drink. Hence, the drink now satisfies all 5 of the human senses.

2. In the medieval ages, it was quite popular to poison your enemies drink. Thus, men would clank their cups together hard and spill their drinks into each otherโs cups. This ensured the man you were drinking with was not poisoning you because if he was, the cheers would end in him poisoning himself. This โCheersโ was a act to trust.

3. In ancient times people believed the sound of glasses clanking together would scare away evil spirits. Therefore, people clanked their glasses together when drinking to ward off said evil spirits. This is also the reason that Jehovahโs Witnesses will not โCheersโ. Since itโs superstitious, they will have no part in it.
know any other origins for โCheers?โ
when you know the words, it is easier to research:
http://www.todayifoundout.com/index.php/2013/05/the-origin-of-toasting-drinks/
Etymology rocks