Update for Bootstrap 4 (2018)
The hidden-* and visible-* classes no longer exist in Bootstrap 4. If you want to hide an element on specific tiers or breakpoints in Bootstrap 4, use the d-* display classes accordingly.
Remember that extra-small/mobile (formerly xs) is the default (implied) breakpoint, unless overridden by a larger breakpoint. Therefore, the -xs infix no longer exists in Bootstrap 4.
Show/hide for breakpoint and down:
hidden-xs-down (hidden-xs) = d-none d-sm-block hidden-sm-down (hidden-sm hidden-xs) = d-none d-md-block hidden-md-down (hidden-md hidden-sm hidden-xs) = d-none d-lg-block hidden-lg-down = d-none d-xl-block hidden-xl-down (n/a 3.x) = d-none (same as hidden)
Show/hide for breakpoint and up:
hidden-xs-up = d-none (same as hidden) hidden-sm-up = d-sm-none hidden-md-up = d-md-none hidden-lg-up = d-lg-none hidden-xl-up (n/a 3.x) = d-xl-none
Show/hide only for a single breakpoint:
hidden-xs (only) = d-none d-sm-block (same as hidden-xs-down) hidden-sm (only) = d-block d-sm-none d-md-block hidden-md (only) = d-block d-md-none d-lg-block hidden-lg (only) = d-block d-lg-none d-xl-block hidden-xl (n/a 3.x) = d-block d-xl-none visible-xs (only) = d-block d-sm-none visible-sm (only) = d-none d-sm-block d-md-none visible-md (only) = d-none d-md-block d-lg-none visible-lg (only) = d-none d-lg-block d-xl-none visible-xl (n/a 3.x) = d-none d-xl-block
Demo of the responsive display classes in Bootstrap 4
Also, note that d-*-block can be replaced with d-*-inline, d-*-flex, d-*-table-cell, d-*-table etc.. depending on the display type of the element. Read more on the display classes