The current query is asking about the word "when" in isolation, which is ambiguous. The simplest, most useful interpretation is to explain the basic uses and meanings of "when" in English, including common sentence structures and examples. Core meanings and uses

• Time inquiries and references: asks about the time or timing of events.
  • Example questions: When is the meeting? When will you arrive?
  • Example statements: I remember when I was a child.
• Conjunctions introducing clauses: connects two clauses to indicate time or conditions.
  • As a conjunction, it can introduce a dependent clause that specifies time: We'll call you when we arrive.
  • It can also introduce conditional or hypothetical scenarios in certain constructions: When given a choice, choose the simplest option.
• Relative pronouns: introduces relative clauses that provide additional information about a noun.
  • Example: The day when we met was sunny.
• Adverbial usage: can function as an adverb modifying a verb to indicate timing.
  • Example: She left when the clock struck midnight.

Common sentence patterns

• Interrogative questions about time
  • When + auxiliary (do/does/did) + subject + base verb: When did you finish the project?
  • When + is/are/was/were + noun phrase: When is the concert?
• Subordinate clauses of time
  • Main clause + when + subordinate clause: I’ll call you when I arrive.
  • Subordinate clause + when + main clause (less common in formal writing): When I arrived, the room was empty.
• Relative clauses
  • Noun + when + relative clause: The year when we moved here was memorable.

Pronunciation and variants

• Pronounced as /wɛn/ in standard English.
• In fast speech, it can sound like /wən/ in some dialects or informal contexts.

Tips for learners

• Distinguish between when as a question word (time inquiries) and when as a conjunction/relative pronoun (linking clauses).
• Practice with paired phrases: “When + will/does/is + …” for questions, “I'll go when …” for dependent timing clauses.
• Pay attention to tense in dependent clauses after “when” (historical events use past tense in the subordinate clause when appropriate).

If you’d like, specify the exact context (e.g., grammar level, example sentences you’re working with, or a particular exercise), and this explanation can be tailored with targeted practice.