What did Eli Whitney develop that shaped American industry for centuries to come?
Answer
Interchangeable parts
While the cotton gin brought fame, the development and implementation of interchangeable parts, driven by government firearm contracts, is described as his second, arguably more enduring contribution that established the basis for modern manufacturing.

Related Questions
What did Eli Whitney develop that shaped American industry for centuries to come?How were mechanical items typically repaired before Whitney's parts standardization system took hold?What was the immediate impetus for Whitney developing his system of standardization?In what year did Whitney secure the contract to supply 10,000 muskets using standardization methods?What specialized tooling did Whitney and his team create to ensure component precision for the arms contract?Which US President visited the Whitney Armory in 1802 to observe the emerging system?What significant historical comparison was made regarding the economic viability of Whitney's system versus European efforts?What economic inheritance did the armory system provide for the North, contrasting with the cotton gin's effect?What ancillary item, requiring repeatable and accurate construction, did Whitney also design and patent?What year did Eli Whitney pass away?