A Squish is a platonic crush, where one where one strongly desires to be close to a particular person, but not in a romantic way. It is common for aromantic and other a-spec people to experience squishes, though it is not exclusive to them, and not all a-spec people experience squishes. It is defined as the desire to be close friends with a particular person, or to become closer friends with a particular person if one is already friends with them. It may also be used for a desire to be in a queerplatonic relationship with a particular person, or as any sort of crush that is not romantic or sexual in nature.
A squish can possibly include thinking about the person in question, enjoying being around them, getting flustered around them, wanting the person to consider oneself a friend or a best friend, and possibly a desire physical closeness with them. However, one does not consider their squish as a romantic partner or potential romantic partner. Any form of emotional connection or physical closeness is not considered to be romantic in nature by the person with the squish.
Having squishes is not the same as a general "desire for friends". A squish is targeted towards a specific person. One can desire friends without feeling squishes. Someone who does not experience squishes may call themself aplatonic.