What is the meaning of sketch?

noun

• Preliminary drawing for later elaboration.
  • usage: "he made several studies before starting to paint"
  • synonyms: study
• A brief literary description.
  • synonyms: vignette
• Short descriptive summary (of events.
  • synonyms: survey, resume
• A humorous or satirical drawing published in a newspaper or magazine.
  • synonyms: cartoon

verb

• Make a sketch of.
  • usage: "sketch the building"
  • synonyms: chalk out
• Describe roughly or briefly or give the main points or summary of.
  • usage: "sketch the outline of the book"; "outline his ideas"
  • synonyms: outline, adumbrate