Note on the previous block, and more:

the electronics / tech industry has conventional terminology that makes every beginner raise their eyebrows. jumper wires ends are labelled "male" or "female" depending on whether they contain a protruding metallic pin, or a receiving end for the pin to plug into. The much more unsettling "technosocial metaphor", is one used for i2c communication. The device that drives the clock is called the "master" device, and the sensors/components that synchronize to the clock are called "slave" device. The i2c protocol is briefly described at the end of this note.

alternative terminology to use: active/standby, writer/reader, parent/child, and leader/follower

from the WIRED article (the previous block), I pulled the following:
"The “master/slave” metaphor in technology dates back to at least 1904, describing a sidereal clock system at an observatory in Cape Town, according to a 2007 essay by Ron Eglash, a professor at the University of Michigan. The words may have been chosen to emphasize the innovation, Eglash wrote: “The concept of a free master that did no work and a slave that followed the master’s orders made for a vivid, if ethically suspect, technosocial metaphor.”

In the 21st century, the language is increasingly questioned. Eglash and others point to a 2003 memo from the Los Angeles County Office of Affirmative Action Compliance, responding to an employee’s complaint about using master and slave in computer contexts. The county agency declared the words “not an acceptable identification label,” Eglash wrote, which incited debate in the pre-Twitter internet era.

Other organizations have more recently revised language that could be seen as rooted in racism. The Django web development platform changed master and slave to leader and follower in 2014, and the open-source content-management system Drupal went with primary and replica the same year. The Python programming language dropped both master and slave in 2018, which also generated some controversy among users"

i2c allows two pins on an arduino (and many other devices of course) to send and receive data to 100+ other devices. it is extremely convenient because instead of needing dozens/hundreds of pins, the data is compressed in the time domain and send through these two pins as a sequence.