Technical Infrastructure- historically, a division inside google which was responsible for the software and hardware infrastructure that runs google. Search, ads, cloud, youtube, etc all ran (run?) on top of TI software and hardware. TI existed before google cloud did and was (is) basically its own cloud with a service API, with borg, google clusters, networking, storage, databases, etc. Historically it was run by Urs (https://en.wikipedia.org/wiki/Urs_H%C3%B6lzle). At some point, TI and cloud got mixed up together to get more TI people to work on Cloud products. Many cloud products represent either TI services or variations/ports/reimplementations of TI services.

TI was absolutely enormous and it was key to google's early and continued scaling of compute and storage. I don't know if it still exists within Google or got renamed, or what.