[--]

Jyutping lou5 tung4
Pinyin lǎo tóng

Definitions (CC-CANTO)
  1. someone with the same name or similar name; fellow mates who are of the same age; a fellow drug addict; a homosexual; an associate; a “crony”; a fellow inmate [colloquial]
Definitions (粵典–words.hk)
  1. 名詞、俚語、香港
    吸毒者​嘅​別​稱​。
    a heroin addict, a drug addict, a fellow drug addict
  2. 近義詞
    道友
  3. 參看
    老童
Examples (Tatoeba—Mandarin-English)
  1. Mandarin
    老同学,你现在在哪儿工作?
    老同學,你現在在哪兒工作?
    lǎo tóng xué , nǐ xiàn zài zài nǎ er gōng zuò ?
    • Old pal! Where are you working now?
Examples (Wiktionary)
  1. Mandarin
    老同学在北京还能聚上一次,太难得。
    老同學在北京還能聚上一次,太難得。
    lǎo tóng xué zài běi jīng hái néng jù shàng yī cì , tài nán dé .
    • It's so rare that old classmates can get together again in Beijing.