In the Bible, did the word “slave” just mean a servant who is set free after seven years?
No. The word “slave” in the Bible meant the same thing that it means today. The passages are given below.
Leviticus 25:44-46
“Your male and female slaves are to come from the nations around you; from
them you may buy slaves. You may also buy some of the temporary residents
living among you and members of their clans born in your country, and they
will become your property. You can bequeath them to your children as
inherited property and can make them slaves for life, but you must not rule
over your fellow Israelites ruthlessly."
Exodus 21:4
"If his master gives him a wife and she bears him sons or daughters, the
woman and her children shall belong to her master, and only the man shall go
free."
Exodus 21:20-21
“Anyone who beats their male or female slave with a rod must be punished if
the slave dies as a direct result, but they are not to be punished if the
slave recovers after a day or two, since the slave is their property."
Follow up questions:
If God did not want us to eat meat, then why did he place animals on the Earth?
Don't only human beings have a soul?
Doesn't the Bible give humans dominion over the animals?