Definition
A sequence is a set of things arranged one after another in a definite order, each following the last. From the Latin sequi, 'to follow,' it stresses succession: not just a group, but a group whose order is paramount. A sequence of events, a DNA sequence, a sequence of steps in a proof — change the order and the meaning can collapse. The word implies a thread running through time or space, where each element earns its place by what comes before it and what it makes possible next.
Examples
Collocations
a sequence of events·in sequence·the correct sequence·a logical sequence·out of sequence
Synonyms
order·succession·series·progression·chain
Antonyms
randomness·disorder
Word family
sequential (adjective)·sequentially (adverb)·sequencing (noun)
In TOEFL & IELTS
Essential for narration and process description — TOEFL integrated tasks and IELTS Task 1 process diagrams both reward 'the sequence of steps'. Signposting words (first, next, subsequently, finally) build a sequence in Writing and Speaking. The adjective sequential ('sequential order') is common in academic English. Keep sequence (ordered succession) distinct from series (a set, order optional).