Initial
The word initial is a term referring to the first part of a Chinese syllable. It is 声母 (shēngmǔ) in Chinese. Most Mandarin Chinese syllables have an initial, but not all. If there is no initial, you might see the symbol "∅-" to signify that.
A Chinese initial cannot be a syllable or a word on its own, and it's difficult to even get recordings of "just the initial" because it's not easy to pronounce an initial clearly without adding at least part of a vowel sound after it.