Definition: An abortion is the termination of a pregnancy by the removal or expulsion of an embryo or fetus from the uterus, resulting in or caused by its death. An abortion can occur spontaneously due to complications during pregnancy or can be induced. (definition from Wikipedia)
Abortion as a term most commonly - and in the statistics presented here - refers to the induced abortion of a human pregnancy, while spontaneous abortions are usually termed miscarriages.
"This year" refers to the period from Jan 1 at 00:00 up to now.
The data on abortions displayed on the Worldometer's counter is based on the latest statistics on worldwide abortions published by the World Health Organization (WHO).
According to WHO, every year in the world there are an estimated 40-50 million abortions. This corresponds to approximately 125,000 abortions per day.
In the USA, where nearly half of pregnancies are unintended and four in 10 of these are terminated by abortion  , there are over 3,000 abortions per day. Twenty-two percent of all pregnancies in the USA (excluding miscarriages) end in abortion.