barrier

A structure that bars passage.

• The bus went through a railway barrier and was hit by a train.
• The bomber had passed through one checkpoint before blowing himself up at a second barrier.

An obstacle or impediment.

• Even a small fee can be a barrier for some students.

A boundary or limit.

• Few marathon runners break the three-hour time barrier.

A node (in government and binding theory) said to intervene between other nodes A and B if it is a potential governor for B, c-commands B, and does not c-command A.

A separation between two areas of the body where specialized cells allow the entry of certain substances but prevent the entry of others.

The lists in a tournament.historical

A martial exercise of the 15th and 16th centuries.historicalin-plural

To block or obstruct with a barrier.transitive