Definition

1. Noun:
   • Milestone / Kilometer marker: A physical post, pillar, or stone erected beside a road or highway to mark distance. It typically shows the number of kilometers from a specific starting point or to a specific destination.
   • Kilometer (km): A common, informal term for the unit of length equal to 1,000 meters, used to express distances.

Usage Examples

• Noun (Milestone):
  • Đường rẽ ở chỗ cây số 5. (The turning is at milestone 5.)
  • Xe hỏng ngay bên cạnh một cây số. (The car broke down right next to a kilometer marker.)
• Noun (Kilometer):
  • Cách nhau ba cây số. (They are three kilometers apart.)
  • Thị trấn đó cách đây khoảng mười cây số. (That town is about ten kilometers from here.)

Advanced Usage

• The word is often used in giving driving or travel directions, referring to specific points along a route.
  • Hãy đi thẳng cho đến cây số 12 rồi rẽ trái. (Go straight until kilometer marker 12, then turn left.)

Variants and Related Words

• Kilômét / Ki-lô-mét (n): The formal, standard term for "kilometer."
  • Tốc độ giới hạn là 80 ki-lô-mét một giờ. (The speed limit is 80 kilometers per hour.)
• Cột cây số (n): Emphasizes the "post" or "column" aspect of the milestone.

Synonyms

• Milestone: A stone or post marking distance.
• Kilometer marker: A signpost indicating kilometers.
• Kilometer (km): A metric unit of distance.

Notes on Usage

• "Cây số" is a compound word, but it functions as a single, fixed unit in modern Vietnamese. Its dual meaning (the physical marker and the unit of distance) is intrinsically linked.
• In everyday speech, when stating a distance (e.g., "three cây số"), it is understood to mean "three kilometers." The context usually makes it clear which meaning is intended.

1. Milestone
   • đường rẽ ở chỗ cây số 5
     the turning is at milestone 5
2. Kilometer
   • cách nhau ba cây số
     three kilometers distant from each other