poop is usually used by children?
I found the meaning of the word "poop" from dictionary as follows and it says that it is particularly used by children or to children. So what is the word used by adults in day-to-day life?.

http://www.macmillandictionary.com/us/dictionary/american/poop_1

[countable] [usually singular] American informal the act of passing waste from your body when you go to the bathroom. This word is used especially by and to children..

Question

poop is usually used by children?
I found the meaning of the word "poop" from dictionary as follows and it says that it is particularly used by children or to children. So what is the word used by adults in day-to-day life?.

http://www.macmillandictionary.com/us/dictionary/american/poop_1

[countable] [usually singular] American informal the act of passing waste from your body when you go to the bathroom. This word is used especially by and to children..

Answer

Talking about intimate body parts and bodily functions is always a tricky decision:

We generally have a choice of

medical terminology  (look in a dictionary)
vulgar and crude language  ( I'm sure you know these words)
baby-talk  (as in your question)
coy euphemisms ( e.g. 'number twos')

You'd use the first to your doctor and the second (perhaps) among close friends. In most other situations, the third is probably the least inappropriate option. So yes, informally, if you don't want sound vulgar, pretentious, or coy, then sometimes adults do say 'poop' (or 'poo' in GB English) . If none of the other words seem right, then sometimes baby-talk is the best choice.

Answer

I think it highly depends on culture and personal preference. Since the dictionary you are citing seems to be a US dictionary, it seems "poop" is commonly used by children in the US culture.

I personally use "poop" rather than "shit" or "dump" merely because I prefer the sound of it. However, the adults (and even the children) in my culture use "shit" more often.