(geometry) Of a triangle, having all three interior angles measuring less than 90 degrees.
(botany) With the sides meeting directly to form an acute angle (at an apex or base)
(medicine) Of an abnormal condition of recent or sudden onset, in contrast to delayed onset; this sense does not imply severity (unlike the common usage).
(medicine) Of a short-lived condition, in contrast to a chronic condition; this sense also does not imply severity.
(orthography, after a letter) Having an acute accent.