finger lime       
noun [ C ] uk/ˈfɪŋ.ɡə ˌlaɪm/ us/ˈfɪŋ.ɡɚ ˌlaɪm/
 指橙树;指橙果实
a small, sour-tasting, green, pink, or red fruit with a long shape, containing many small round parts full of juice; the small tree on which this fruit grows
  Have you ever tasted a finger lime? 你尝过指橙吗? 
 In his kitchen garden there are fabulous things such as finger limes, lychee, and tamarind. 他的厨房菜园里种着一些非常有趣的植物,如指橙、荔枝和酸角。 
 - More examples
 - In Chicago I had a stunning Tom Kha Gai soup with finger limes and lemongrass.
 - The juicy pearls inside the finger lime have been compared to "lime caviar".
 - The finger lime beads are easily sucked up through a straw, adding an extra citrus zing to their cocktails.
 - I purchased a finger lime from a plant nursery last year and have kept it in its pot.