Most scientists fall under deism. They are fine with references to "god", "mother nature", or just "nature", if only to provide a point of reference in a philosophical discussion.
Some scientists fall under theism. They worship a god.
Being religious doesn't necessarily mean believing in a god, it means having faith in something that cannot be proven (scientifically I suppose). Nonetheless, religious and religion are generally associated with a belief in a god.
Atheism, in its simplest use, means not believing in a god. In practice however, extreme atheism often involves disproving god. But atheism does not mean not being religious. All people are religious in some way. We believe in things we cannot prove. I think "how religious" you are depends on how "careful" you are with the conclusions you reach based on your unproven beliefs.
Agnostic is not caring one way or another.
To sum up. All people are religious, they believe in things that cannot be proven. People who reference god or nature in discussions are at least "deistic". People who worship a god are "theistic". People who do not worship a god are "atheistic". People who don't care about god worship are "agnostic".