For questions about sequences of chords, and the relationship of one chord to the next. Typically questions about chord progressions should also be tagged harmony if asking about in depth concepts about them. Questions that are about abstractions of chord progressions use Roman Numeral analysis should also be tagged with Roman-Numeral and analysis if applicable.
Chord progressions can be viewed as harmonic overview of a piece of music. For example, the chord progression
C - Dm - G7 - C can give a lot of information to a fellow musician. Besides just giving the chords, a seasoned musician would also understand the key the piece it is in.
A different word for progression is cadence. Cadences are known e.g. from classical music, Jazz and Pop music.
Where to find more
- Cadences on Wikipedia, as chords on leadsheets
- Chord progressions on Wikipedia, with focus on degrees and common sequences
- Some of the Most Common Chord Progressions in Baroque Major Harmony (pdf)
- The most common cadences (pdf), just name and degrees
- Some Jazz chord progressions on Jazz Guitar -"Jazz Chord Progressions — The Ultimate Guide" on Jazz Library, spelling out basic patterns
- Popular chord progressions on Hooktheory, with examples from Pop music