A barcode: a set of machine-readable lines of varying width placed on products to represent pricing or other such data.

address bar (bar in a web browser that displays the address)

dyke or FTM-staffed bar

gay bar

lesbian bar

bar where women bartenders chat with patrons

a snack bar

(graphical user interface) scroll bar (graphical widget)

the first sight of something / something seen for the first time

one should start a big project with immediate, practical steps; start small / the person who proposes something should be the first one to take practical steps to implement it