
The 1632 Galileo engine shown with nearly broken hemp cords, which is kind of how Galileo tentatively thought what would happen if one filled the above piston and cylinder with air or water and then pulled on handle K until the seal broke, meaning that the "cord of water or air" had been broken, NOT that a vacuum had been formed, as this contradicted the nature abhors a vacuum dictum. [2]

The 1632 Galileo engine shown with nearly broken hemp cords, which is kind of how Galileo tentatively thought what would happen if one filled the above piston and cylinder with air or water and then pulled on handle K until the seal broke, meaning that the "cord of water or air" had been broken, NOT that a vacuum had been formed, as this contradicted the nature abhors a vacuum dictum. [2]

In science, vacuum break, vacuum breaking, or the premise that when the “vacuum broke”, refers to the Aristotle-themed premise that vacuums cannot exist, and that what seems to be the formation or start of a vacuum, in maximum amount of force required to pull a piston out of, e.g. a sealed piston in a Galileo engine, or the two hemispheres of the Magdeburg hemispheres, is the breaking of a air or water conceptualized like a “sponge” or “rope”, as conceptualized by Galileo (Dialogue Concerning the Two Chief World Systems, 1632), that when pulled hard enough “breaks”, but in reality is the breaking point when the force of the pull overcomes the weight of the atmospheric pressure or column of air, up to the Karman line boundary of space.

Quotes
The following are related quotes:

“If hemp or steel cords break under excessive weight, what doubt could we have that a cord of water will likewise break? In fact, it will break more easily, insofar as the parts of water, becoming separated from one another, do not have to overcome resistances other than that of the vacuum that is created at the moment of division. This is because in the case of iron and other solids, there is a very strong and tenacious attachment of the parts that is absent in water.”
— Galileo (1630), “Letter to Giovani Baliani” (Ѻ), Aug 6

“In spite of its advance over its predecessors, the Newcomen engine was slow and inefficient. As has been said, it operated at atmospheric pressure or less. It used steam only to create by condensation a vacuum which allowed the atmosphere to press down upon the piston. Its working beam was balanced to rock again as the vacuum broke and steam reentered the cylinder. The expansive force in the steam was not used to push or pull anything.”
— Richard Kirby (1956), Engineering in History (pg. 166) [1]

References
1. Kirby, Richard; Withington, Sidney; Darling, Arthur; and Kilgour, Frederick. (1956). Engineering in History (pg. 169-72). Courier, 1990.
2. (a) 5. (a) Galilei, Galileo. (1638). Discourse and Mathematical Demonstration of the Two New Sciences (Discorsi e dimostrazioni Matematiche Intorno a Due Nuove Scienze) (pg. 15). Leiden.
(b) Boschiero, Luciano. (2007). Experimental and Natural Philosophy in Seventeenth-century Tuscany (pg. 118). Springer.
(c) Galileo. (1632). Dialogues Concerning the Two New Sciences (translators: Henry Crew and Alfonso Salvio) (Lagrange quote, pg. v; stone column, pg. 7; engine, pg. 14). Macmillan, 1914.