Slavery
Slavery is defined by Merriam Webster as "the state of a person who is a chattel of another." Despite being a well-known phenomenon, it is difficult to precisely define. Significant debates continue to rage over whether slavery is merely historical or whether it continues till this day in certain forms.
Competing definitions
The scholar and historian Dr. Jonathan AC Brown has described the various definitions that have been proposed for the concept of "slavery." He argues that there is no single all-encompassing definition that works in all times and places - each definition has its shortcomings one way or another. In addition to Dr. Brown, other scholars have noted the difficulty of defining slavery; for example the scholar of slavery in Western civilization David Brion Davis has said, "the more we learn about slavery, the more difficulty we have defining it."[1]
Refusal to define: slavery by recognition
According to this point of view, instead of giving an actual definition of slavery, we can simply say that slavery is known when recognized. If we see a particular scenario and it seems like it's slavery, then it probably is, and if it seems OK to us then it probably isn't slavery.
Dr. Brown points out that there were many instances of slavery that wouldn't look like slavery to the modern eye - for example, many of the Ottoman grand viziers were legally slaves.[1]
Slavery as a legal condition
Something something something.
Slavery as lack of freedom
Problem: we always don't have freedom.
Slavery as property
Doesn't include modern slavery.
Slavery as class
Too broad?
Slavery as violent coercion
Again too broad.
Modern slavery
An interesting phenomenon.