Definition

1. Noun (Mathematics):
   • A straight line: A line with no curvature; the shortest distance between two points. It extends infinitely in both directions.
   • A direct route: A path that does not bend or turn.

Usage Examples

• Noun (Mathematics):
  • Hãy vẽ một đường thẳng qua hai điểm A và B. (Draw a straight line through points A and B.)
  • Trong hình học, đường thẳng là một khái niệm cơ bản. (In geometry, a straight line is a fundamental concept.)
• Noun (Route):
  • Đi đường thẳng này đến cuối sẽ thấy bưu điện. (Go straight on this road to the end and you will see the post office.)

Advanced Usage

• "đường thẳng đứng": vertical line.
  • Mặt tiền nhà có những đường thẳng đứng. (The house facade has vertical lines.)
• "đường thẳng ngang": horizontal line.
  • Bức tranh được chia cắt bởi một đường thẳng ngang. (The painting is divided by a horizontal line.)
• "theo đường thẳng": as the crow flies; in a straight line.
  • Khoảng cách theo đường thẳng chỉ 5 km. (The distance as the crow flies is only 5 km.)

Variants and Related Words

• Đường (n): road, path, line, sugar.
• Thẳng (adj): straight, direct.
• Đường cong (n): curved line.
• Đường gấp khúc (n): polygonal line, broken line.
• Tia (n): ray (a line with one endpoint).

Synonyms

• Line: a long, narrow mark or band.
• Direct route: a path without detours.

Related Idioms

• Thẳng như ruột ngựa: (lit. straight as a horse's intestine) meaning very straightforward or blunt in speech.
  • Anh ấy nói chuyện thẳng như ruột ngựa. (He speaks very bluntly.)
• Đi đường thẳng: to go straight (often used literally for directions, but can imply honest conduct).
  • Cứ đi đường thẳng thì không sợ lạc. (If you go straight, you won't get lost.)

1. Straight line