Where does “Indian relay” come from?

Indian relay (English) comes from English relay, from English lay, from English Lee, from Irish Laoi, from Middle Irish láed, from English loid, from English celluloid, from English cellulose — Forms agent nouns from verbal roots.

Indian relay (English): A sport developed by the Prairie Amerinds / Great Plains Indians, where competitors race thrice around a horsetrack bareback on horses, where the racer must jump off one horse and onto another at the end of each lap

Definitions

  1. A sport developed by the Prairie Amerinds / Great Plains Indians, where competitors race thrice around a horsetrack bareback on horses, where the racer must jump off one horse and onto another at the end of each lap

Ancestry of “Indian relay”, step by step

Indian relay traces back through two separate lines of ancestry.

via English relay

StepLanguageWordMeaning
1EnglishrelayA new set of hounds; A new set of horses kept...
2EnglishlayTo place down in a position of rest, or in a...
3EnglishLeefor someone who lived near a meadow (the Anglo-Saxon for meadow being ley or leag)
4IrishLaoilay, song
5Middle Irishláed
6EnglishloidA lock-picking tool made from a piece of...
7EnglishcelluloidAny of a variety of thermoplastics created from...
8EnglishcelluloseA complex carbohydrate that forms the main...
9Frenchcellulosecellulose
10Frenchcellulecell; table cell
11Latincellulasmall room, especially that of a slave; humble...
12Latin-ulusUsed to form a diminutive of a noun, indicating...
13Proto-Italic-olos
14Proto-Italic-elosForms desubstantival and deadjectival diminutive nouns
15Proto-Indo-European-e-lós
16Proto-Indo-European-lósForms agent nouns from verbal roots

via English indian

StepLanguageWordMeaning
1EnglishindianOf or relating to India or its people; or (formerly) of the East Indies
2Middle EnglishIndien
3Anglo-NormanindienIndian
Every word from Proto-Indo-European -lós