When you think you know someone or something quite well or in detail, and it turns out you don't really know that someone or something at all, you only know them in a shellular way. This can be in terms of a person / romantic relationship, or with a body of knowledge where a discovery makes the prior body of knowledge utterly obsolete.
I thought my boyfriend was awesome, until I found out that he secretly collects the teeth of farm animals and keeps them in a root cellar that I didn't even know he had. All this time, I thought we were close, but we only had a shellular relationship.
by Fickle Bastard October 20, 2010