You won't find the result even if you have a printed dictionary, unless you learn the basic verb conjugation. When you look up a verb, you need to know the dictionary form of the verb.
"motte" is a conjugated form of "motsu", motteimasu is a phrase consists of motsu + imasu, and "imasu" is polite form of "iru".
It's like you won't find "owns" as an entry in English dictionaries.