What is the difference among col-lg-*, col-md-* and col-sm-* in Bootstrap?

Question

What is the difference among col-lg-* , col-md-* and col-sm-* in Twitter Bootstrap?

Answer 1

well it's used to tell bootstrap how many columns are to be placed in a row depending on the screen size-

col-xs-2

would show only 2 columns in a row in extra small(xs) screen, in the same way as sm defines a small screen, md(medium sized), lg(large sized), but according to bootstrap smaller first rule, if you mention

xs-col-2 md-col-4

then 2 columns would be shown in every row for screen sizes from xs upto sm(included) and changes when it gets next size i.e. for md up to lg(included) for a better understanding of screen sizes try running them in various screen modes in chrome's developer mode(ctr+shift+i) and try various pixels or devices