Grammar / Tense
The tense of a verb indicates when the action happened or whether or not the action is completed.
Present
Present tense indicates action that is happening now.
Aorist
Aorist indicates a snapshot of a past action.
Second aorist
Second aorist is the same as aorist, indicating a past action, but the way the conjugation is formed is different. This is similar to how some verbs in English mark past by adding "-ed" (e.g. helped) while other mark past by changing the vowel in the middle of the verb (e.g. sang).
Future
Future indicates a future action.
Second future
Second future is a rare form of future.
Imperfect
Imperfect indicates a past action that is not completed.
Pluperfect
Indicates a past action that occurred prior to an aforementioned time.
Perfect
Perfect indicates a completed past action which produced results which are still in effect up to the present.
Second perfect
Second perfect is the same as perfect, but the way the conjugation is formed is different.
No tense (adverbial imperative)
Verb-like adverbial imperative.