Once

"Once" is an adverb indicating that something happens a single time or on one occasion. It emphasizes a single occurrence or event, often suggesting that something happened in the past but not repeatedly. For example, saying "I visited Paris once" means the visit happened one time. It can also imply that the event is sufficient or sufficient for a particular purpose, such as "Once I understand the rules, I can start." Overall, "once" helps specify the timing or frequency of an event, highlighting that it happened one time or at a specific moment.