(US) That which is certain.

(informal) An action that yields undesirable results to its subject.

(from Kantian philosophy on) A thing as it is independent of any conceptualization or perception by the human mind, postulated by practical reason but existing in a condition which is in principle unknowable and unexperienceable.

Early in the morning. / Straight away, very soon.

The basic idea of how to do something. / Used other than figuratively or idiomatically: see first, thing.

(informal) Something that is conventionally accepted as good beyond doubt.

(sequence) Used to introduce an additional item in a possible sequence

(sequence) Used to introduce the first item in a possible sequence

A considerable amount; a lot.

(chiefly UK) Something done habitually or according to social norms, expectations, etc.