TOEFL IELTS air Definition The invisible gaseous substance that surrounds the Earth 中文 包围地球的不可见的气体 Example "We need oxygen-rich air to breathe." Sign in to save TOEFL PDF — $25 IELTS PDF — $25 ← aim airborne → Study tips featuring "air" TOEFL Academic Vocabulary: Study by Topic Boost Your IELTS Writing With Precise Vocabulary Related words TOEFL brighten GRE abash GRE abate GRE abbreviate GRE abbreviation SAT abdicate GRE abduct SAT abet GRE abhor GRE abide SAT abject TOEFL ablaze