From chain +‎ -let.

chainlet (plural chainlets)

1. A small chain.
   • 1805, Walter Scott, “(please specify the page)”, in The Lay of the Last Minstrel: A Poem, London: […] [James Ballantyne] for Longman, Hurst, Rees, and Orme,[…], and A[rchibald] Constable and Co.,[…], →OCLC:

     What plumage waved the altar round ,
     How spurs and ringing chainlets sound

   • 1849, Currer Bell [pseudonym; Charlotte Brontë], “The First Blue-Stocking”, in Shirley. A Tale.[…], volume III, London: Smith, Elder and Co.,[…], →OCLC, pages 84–85:

     Her pure white dress, her fair arms and neck, the trembling chainlet of gold circling her throat, and quivering on her breast, glistened strangely amid the obscurity of the sick-room.

2. A chain (totally ordered set) that has a finite number of elements.

• “chainlet”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.

• cathelin, chat line, chatline, ethnical