1. Having existed for a long time
   "a longstanding friendship"; "the longstanding conflict"

See also: long

• Old World rabbit
• Old World robin
• Old World scops owl
• Old World vulture
• Old World warbler
• Old world white pelican
• Old World yew
• old-age insurance
• old-age pension
• old-age pensioner
• old-fashionedness
• old-field toadflax
• old-hat
• old-line
• old-maid's bonnet
• old-maidish
• old-man-of-the-woods
• old-time
• old-womanish
• old-world
• olde worlde
• olden
• Oldenburg
• older
• Oldfield