Typically, a root plus a suffix forms a stem, and adding an ending forms a word.
$${\displaystyle \underbrace {\underbrace {\mathrm {root+suffix} } _{\mathrm {stem} }+\mathrm {ending} } _{\mathrm {word} }}$$ See more

Roots were occasionally created anew within PIE or its early descendants. A variety of methods have been observed.
Root extensions See more

• American Heritage Indo-European Roots Index
• Database query to the online version of Pokorny's PIE dictionary
• Index to the online version of Pokorny's PIE dictionary See more

In its base form, a PIE root consists of a single vowel, preceded and followed by consonants. Except for a very few cases, the root is fully … See more

The meaning of a reconstructed root is conventionally that of a verb; the terms root and verbal root are almost synonymous in PIE … See more

• Lexikon der indogermanischen Verben ('Lexicon of the Indo-European Verbs', in German), a lexicon of PIE verbal roots See more