Thought

This Kanji is usually pronounced as "Omoi" or "sou"
By itself, it means "thoughts/feelings/emotions/imagination".

Some common forms of the word when used:

-Omoi-
想い出 （omoide): memories
片想い (kata omoi): unrequited love

-Sou-
感想 (kansou): impressions; thoughts
空想 (kuusou): daydream; fantasy
思想 (kansou): thought; idea
発想 (hassou): conceptualization
理想 (risou): ideals

Note:

想い (omoi) is closely related to 思い。
想い出 can be written as 思い出。
Also, 片想い can be written as 片思い。
But, "思" cannot be read as "sou", unlike "想"。
So, you cannot write "感思"。

Both "想" and "思" mean to think.
今日は雨が降ると思う
(kyou ha ame ga furu to omou)
I think that it will rain today.

*** {phrase} + と思う is a common way of expressing one's opinion.