Miniaturized is the -ed form of miniaturize. As a past verb, it means someone already made the thing very small: “They miniaturized the camera.” As an adjective — and this is the use you will see most — it describes a thing that is now in that tiny designed form: miniaturized electronics, a miniaturized microphone, a miniaturized motor. The feel is still technical. A miniaturized device is not merely small and cute. It is small because engineers packed a job that used to need a bigger machine into a much smaller one. Product pages and science writing love this word. Everyday English more often just says small, tiny, or pocket-sized. Do not mix it up with miniature in front of a noun (a miniature railway, a miniature horse). Miniature there means “a tiny version of the real kind”. Miniaturized points at the shrinking of a working machine, especially electronics. British spelling may show miniaturised.