biển hồ

biển (“sea”) +‎ hồ (“lake”).

• (Hà Nội) IPA^(key): [ʔɓiən˧˩ ho˨˩]
• (Huế) IPA^(key): [ʔɓiəŋ˧˨ how˦˩]
• (Saigon) IPA^(key): [ʔɓiəŋ˨˩˦ how˨˩]

biển hồ

1. large lake (with a vast expanse of water like the sea)

When capitalised, this can refer to a number of large lakes as such, most notably T'Nưng Lake in Vietnam and Tonlé Sap in Cambodia.