Direct answer: Creosote tar usually means tar-derived creosote or a creosote-rich tar product used for preserving outdoor wood. The exact meaning depends on whether it came from coal tar, wood tar, or another tar source.
Creosote is formed or separated through tar distillation and pyrolysis chemistry. Wood-tar creosote and coal-tar creosote have different origins, and modern industrial wood preservation is especially associated with coal-tar creosote.
Creosote is famous for treating railway sleepers, utility poles, marine piles, and other outdoor timber exposed to decay. In many places, it is now tightly controlled, restricted to industrial or professional uses, or subject to review because of health and environmental concerns.
Do not use creosote tar as a casual synonym for pine tar. Pine tar is a traditional wood tar. Coal-tar creosote is an industrial pesticide and preservative with a much stricter hazard profile. Wood-tar creosote is a different historical fraction again.
In short: Creosote can be derived from tar distillation. Coal-tar creosote is a major industrial wood preservative. Use is regulated or restricted in many jurisdictions. The word creosote covers several related but different materials.