The actual unit Aristotle used was the "mna". A mna was 100x as heavy as a drachma. According to Wikipedia (which is always right except when it's wrong) the most commonly used standard in ancient Greece made a drachma weigh about 4.3g, in which case a mna would be about 430g, compared with 454g for a pound weight. So "pound" or "lb" is a pretty good translation for "mna".

(The "mna" has rough equivalents in other ancient Near Eastern cultures. There's at least one "mina" in the New Testament, and in the famous "writing on the wall" at Belshazzar's feast -- MENE MENE TEKEL PHARSIN -- "mene" is basically the same word as "mna".)