Tar n. : A sailor; a seaman.

Tar n. : A thick, black, viscous liquid obtained by the distillation of wood, coal, etc., and having a varied composition according to the temperature and material employed in obtaining it.

Tar v. t. : To smear with tar, or as with tar; as, to tar ropes; to tar cloth.

Example:
How do I remove Tar from wood decking?

Taxonomy
tarball, tar archives, UStar, tar file, TOC, blocks, tar format, checksum, tape, Compression, GNU tar, gzip, bzip2, tape archive, archive formats, extension, tar.gz, header block.

Defination from the web:
... In computing, tar (derived from tape archive) is both a file format (in the form of a type of archive bitstream) and the name of a program used to handle such files. ...