Rhythm/articulation
Pitch
Timbre/orchestration
Dynamics etc.
100

The speed of the beat.

What is tempo?

100

The sounding of multiple pitches at the same time. 

What is harmony? 

100

Violins, violas, cellos, and double basses. 

What are string instruments?

100

The Italian term for "soft"

What is "piano"?

200

A repeating pattern of strong and weak beats (e.g., 1-2-3 or 1-2-3-4)?

What is meter?

200

Unstable chords, not consonant. 

What is dissonant? 

200

A set of large drums in the Western classical orchestra. 

What is timpani?

200

A gradual increase in dynamics. 

What is a crescendo? 

300

Smooth, the opposite of staccato.

What is legato?
300

The perceived highness of lowness of a sound. 

What is register?

300

A high-pitched, small flute. 

What is a piccolo?

300

The number of "layers" in a piece and the relationship between those layers

What is texture?

400

The length of the notes. 

What is rhythm? 

400

Keys and scales that have dark, stormy, or unhappy connotations?

What is minor? 
400

An Italian word for "everyone," meaning the whole orchestra is playing. 

What is tutti? 

400

A musical part that provides support for a melody. 

What is an accompaniment?