span noun
1 length
ADJ. full | broad, wide a broad span of interests | clear The bridge has a clear span of 36 metres. | 12-foot, 500-metre, etc. | wing (also wingspan) The bird has a 1-metre wingspan.
2 length of time
ADJ. long | short | 10-day, 2-week, etc. | entire | allotted The speech continued well beyond its allotted span. | time | life (also lifespan) | attention, concentration, memory He has a short attention span.
VERB + SPAN cover The book covers the entire span of Arab history.
PREP. over a/the ~ Developments were monitored over a span of two years.
PHRASES a span of time/years
You can also check other dicts: span (English, 中文解释 ), wordnet sense, Collins Definition