The 7-letter word meaning to abate is 'subside', which signifies becoming less intense or widespread, fitting the question's criteria.
The 7-letter word that means to abate is subside. When looking at the options provided: subside, diminish, decrease, and dwindle, only subside meets the criteria of having 7 letters. The terms diminish, decrease, and dwindle all signify a reduction or lessening, much like abate, but they do not satisfy the requirement of having 7 letters.
To abate often means to become less intense or widespread, and subside captures this meaning accurately. Subside is related to things becoming less severe or lowering in intensity, often used in reference to feelings or natural phenomena such as storms or emotions.