According to the Online Etymological Dictionary, vacuum entered English in the 1540s directly from Latin as the substantivized, neuter form of the adjective vacuus. The earliest use was as an abstract, non-count noun denoting the emptiness of space, later any void or empty space, for which one could use the Latin plural vacua or simply tack on ... +1 It seems that vacuum is the odd word out when placed in a lineup with (for example) continuum, individuum, menstruum, and residuum.

Understanding the Context

I don't know why the -uum in vacuum came to be pronounced differently from the -uum in the others, but to judge from the pronunciation offered in John Walker's A Critical Pronouncing Dictionary, and Expositor of the English Language (1807), 'twas not always thus. If a 'vacuum cleaner cleaner' is a machine for cleaning vacuum cleaners, then the person who cleans the vacuum cleaner cleaner would be a 'vacuum cleaner cleaner cleaner'. Is the pope catholic? Do vacuum cleaners suck?

Key Insights

Is water wet? Is the hypotenuse the longest side of a triangle? Does a bear live in the woods? I’ll answer you with my favorite ‘Y’ word—Yes! Is the sky blue?

Final Thoughts

I totally ‘scored’ getting asked by you. Yes! How do you spell yes? Would you take ‘yes’ for an answer? I haven’t said no ... (In a vacuum, “Am I not?” could only be construed as some sort of philosophical counter-Descartian pondering.) In light of this dependence, the comma is more apt then the semicolon.

A talent/knowledge vacuum is created as talent redundancy has been overlooked and nobody else knows how to do Sara's job, then that leg of the company experiences failure until a solution for Sara's absence is resolved. The vacuum tube was soon replaced by semi-conductor materials. The technology was named solid state electronics because, semi-conductor materials, like vacuum, are actually insulators that can conduct more or less when activated. The stories about finding bugs in vacuum tubes and never seemed quite convincing; I suspect the better question is to ask about the origin of "bug" in engineering (going back further than computers).