What Are Compound Words? A compound word is formed when two words are combined to make a new word. It is one of the ways in which the English language is flexible and always changing, as compound words allow people to create new words as the need arises. For example, you might use “in” and “side” to create the compound word “inside”.
The concept of "word" is usually distinguished from that of a morpheme, which is the smallest unit of word which has a meaning, even if it will not stand on its own together or in other small words. In many languages, the notion of what constitutes a "word" may be learned as part of learning the writing system.
Hollow definition, having a space or cavity inside; not solid; empty: a hollow sphere. See more.
Breakthrough definition, a military movement or advance all the way through and beyond an enemy's frontline defense. See more.
What - English Grammar Today - a reference to written and spoken English grammar and usage - Cambridge Dictionary
Word stress, also called lexical stress, is the emphasis a speaker places on a specific syllable in a multi-syllable word. ... Word stress in compound words.