This is the point in a pregnancy when the mother can feel the fetus move. It’s used to denote the first time this happens, so it’s the quickening, meaning it’s a singular event that either has or hasn’t occured.
Wikitionary states that an archaic definition of “quick” is “alive.” Before the advent of modern medicine, the first feeling of fetal movement would be the first proof for a woman that she was pregnant.
The quickening has been used in many legal contexts over the years to determine if a woman is pregnant. It’s mentioned in many laws about abortion, and was sometimes used to determine if a woman could be punished for a crime. (Though, it’s hard not to notice that it’s a very personal thing. Only the pregnant woman knows if quickening has occurred, so she could say it had or hadn’t, depending on what would give her the most benefit.)
Why I Looked It Up
When Roe v. Wade was overturned in the summer of 2022, I watched a long legal analysis of the case, and I was surprised to hear how often the phrase was written into law. I looked it up to see if there was a precise legal definition of it. (But, again, I’m confused about how this can be verified in any legal sense – no one knows but the mother.)
Added on April 4, 2023
In the biography Leonardo da Vinci, there’s a passage about Da Vinci’s plan for a comprehensive study of anatomy:
This work should begin with the conception of man, and describe the nature of the womb and how the fetus lives in it, up to what stage it resides there, and in what way it quickens into life…