Blackball, a pejorative term used to represent the Black baseball movement including the formation of Negro league baseball

Blackball (pool), a variant of pocket billiards, sanctioned by the World Pool-Billiard Association, and popular in the UK and Australia among a few other places, and closely related to the American-style game of eight-ball

"Blackball", a nickname for the letter  i  flag among the international maritime signal flags, featuring a black solid circle on a yellow background, and having specific additional meanings in certain contexts ("no surfing allowed in this area" at lifeguarded beaches, "no diving allowed in this area" at swimming pools, "gale warning" in a harbor, etc.)

Blackball Branch a branch railway line to Blackball, New Zealand (see "Geography" above).

Blackball, New Zealand, a small town located on the western coast of the South Island of New Zealand; see also Blackball Branch in the "Transportation" section, below.

"Blackball" (Offspring song), a song on their 1989 self-titled album

Blackball, a 2003 film starring Paul Kaye

Blackballing, ostracizing someone socially, e.g. prevention of finding local or field-specific employment, blacklisting from a club or other organization, etc. The name derives from an early voting system.

Blackballed: The Bobby Dukes Story, a 2004 film starring Rob Corddry

"Blackball", a song by the industrial band KMFDM, on their 2003 album WWIII

Black Ball Line (trans-Atlantic packet), a fleet of packet ships running between Liverpool and New York, the first scheduled trans-Atlantic service, founded in 1817

Blackball Records, a record label that releases music from the punk band Jawbreaker among others

Black Ball Line, a name for the Puget Sound Navigation Company's ferry system (British Columbia, Canada, and Washington state, US)