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The relation beween Baseball and Sports is called hypernym.
Here is a snippet out of WordNet's baseball hypernym hierarchy:
S: (n) baseball, baseball game, ball (a ball game played with a bat
and ball between two teams of nine players; teams take turns at bat
trying to score runs) "he played baseball in high school"; "there was
a baseball game on every empty lot"; "there was a desire for National
League ball in the area"; "play ball!" direct hyponym / full hyponym
domain term category direct hypernym / inherited hypernym / sister
term S: (n) ball game, ballgame (a field game played with a ball
(especially baseball)) S: (n) field game (an outdoor game played on a
field of specified dimensions) S: (n) outdoor game (an athletic game
that is played outdoors) S: (n) athletic game (a game involving
athletic activity) S: (n) sport, athletics (an active diversion
requiring physical exertion and competition) S: (n) diversion,
recreation (an activity that diverts or amuses or stimulates) "scuba
diving is provided as a diversion for tourists"; "for recreation he
wrote poetry and solved crossword puzzles"; "drug abuse is often
regarded as a form of recreation" S: (n) activity (any specific
behavior) "they avoided all recreational activity" S: (n) act, deed,
human action, human activity (something that people do or cause to
happen) S: (n) event (something that happens at a given place and
time) S: (n) psychological feature (a feature of the mental life of a
living organism) S: (n) abstraction, abstract entity (a ...
