The commentaries to MN118 insist that “body” here means the full length of the breath, but this is unlikely in this context, for three reasons.
Note 2. The commentaries insist that “body” here means the full length of the breath, but this is unlikely in this context, for three reasons: (a) The first two steps already require being aware of the entire length of the breath. Otherwise, the meditator wouldn’t know if a breath was short or long. (b) The fourth step — without further explanation — refers to the breath as “bodily fabrication.” If the Buddha were using two different terms to refer to the breath — “body” and “bodily fabrication” — in such close proximity, he would have been careful to signal that he was redefining his terms (as he does below, when explaining that the first four steps in breath meditation correspond to the practice of focusing on the body in and of itself as a frame of reference). But he doesn’t. (c) As AN 10:20 indicates, the fourth step refers to bringing the mind to the fourth jhāna, a state in which in-and-out breathing grows still (SN 36:11; AN 10:72) and the body is filled with pure, bright aware...