1 PREFIX (加在计量单位之前)表示“兆”，“百万” Mega- is added to nouns that refer to units of measurement in order to form other nouns referring to units that are a million times bigger. (加在计量单位之前)表示“兆”，“百万”
2 PREFIX (与名词、形容词构成合成词，强调大小、性质或重要性) Mega- combines with nouns and adjectives in order to emphasize the size, quality, or importance of something. (与名词、形容词构成合成词，强调大小、性质或重要性) [informal, emphasis]