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Experiment	An experiment is a planned operation carried out under controlled conditions. Example: Joe randomly picks a card from a standard (52 card) deck of cards.
Event	An event is a possible result from an experiment. Example: "Joe picks a heart." He could pick it many different ways. Yet the card being a heart is the event.
Trial	A trial is the action that results in an event. Example: "Joe picks a card." He may or may not get a heart. Yet without him picking a card, you won't know.
Outcome	The result of an experiment is called an outcome. Example: "Joe picks the Jack of Hearts." This specific detail of what happened is the outcome. Many different outcomes might be part of the same event. That is, there are many ways Joe could have picked a heart--all would be outcomes which are part of the event "Joe picks a heart."
Probability	In general, the probability of an event is the ratio . Example: The probability Joe picks a heart is 13/52. There are 13 different outcomes which result in a heart. There are 52 total possible outcomes. Note: We always find probability of events. We note the probability of an event, E, as P(E).
Complement	The complement of an event, E, is when E does not happen. That is, the complement of E is all the other outcomes of an experiment which do not result in event E. Example: The complement of "picking a heart" is "not picking a heart." Note that P(E) + P(E complement) = 1.
Notation	Notation is a shorthand method we communicate efficiently through writing. Examples: P(E) means the probability of event E happening.   P(E | F) means the probability of event E happening given that F has already happened.