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.