Its main meaning is of course to refer to the way one says a word with respect to sound. W.E.B. DuBois's surname is pronounced "DuhBOYS," but most people with that surname prefer the original French pronunciation, "Doo-BWAH."
But in scientific papers, its other meaning is much more useful. "Pronounced" can also refer to magnitude. It can mean the degree to which something sticks out from its surroundings either literally or metaphorically. You could say it means "marked," "obvious," or even "big" in magnitude but it has no connotations of direction (think speed vs velocity). Something can have pronounced smallness.
"The mountain has a pronounced false summit that many people mistake for the true summit. Both are visible when the mountain is viewed from the west."
This word is very good for when saying something inherently positive/affirmative or negative could be confusing.
"The rate of erosion on the mountain became less pronounced over time." (Erosion slowed down but did not reverse. Saying the erosion rate got higher or lower might make the reader wonder if you're talking about elevation or about restoration.)
"The first sea cliff has a dropoff of 400 feet and the second one has a dropoff of 250 feet. The first dropoff is more pronounced." (Asking which one is higher or which one is deeper could necessitate getting very wordy.)
"The patient's hypoglycemia grew more pronounced over time" means that the hypoglycemia grew more severe, that the blood sugar got even lower. If you say the hypoglycemia increased, someone reading too fast might think that the blood sugar level itself increased.
(Please retain the reference in reprint: http://www.letpub.com/index.php?page=author_education_pronounced)