Stroke

The line that builds a letter, thick or thin, the first decision a typeface makes. Everything else is how the strokes meet.

Every letter is strokes before it is anything else, and a typeface's character lives in how those strokes behave: their thickness, how much they vary between thick and thin, how they end. High stroke contrast reads as refinement and cost; even monoline strokes read as engineering.

Stroke contrast also sets what a face can survive. Fine hairlines shatter at small sizes and glow shut on dark screens; sturdy even strokes shrug both off. When display type must carry elegance and body type must carry information, the split is usually a decision about strokes.