Does the use of the same Greek word, "parousia", which means coming or
presence, in all the passages of 1 Thess 4; 2 Thess 2; Matt 24 indicate that
since the same word is used it is the same event?
And what about Epiphaneia (appearing/brightness) in 2 Timothy 4:8 & 2 Thessalonians 2:8?
Or Aapokalupsis (coming/revelation) in 1 Corinthians 1:7 & Romans 2:5?
Or Episunago (gather together) in 2 Thess 2:1 & Mark 13:27?
Or Anastasis (resurrection) in 1Co 15:21 & Rev 20:4-5?
Typically, neither people, nor the Bible, use words in such a way as to
require the conclusion: "Same word, therefore, of necessity it is the
Words are useful precisely because they can be applied to many different situations and events.
Parousia can refer to all sorts of different things, that are even totally unrelated to the return of christ at all. 1Cr 16:17, 2Cr 7:6, 2Cr 10:10, Phl 2:12. Words, by definition, are versatile and are useful because they can describe far more than one specific thing. If we had to invent a new word every time we wished to express a new idea or discuss a new event, things would be quite confusing. Even the word for rapture, harpazo, from 1 Thess 4:17, is used for all sorts of different events, including the arrest of Paul in Acts 23:10.
The reason why parousia, "presence, or coming" refers to both the return of Christ at the pretribulation rapture and at the return of Christ to the earth at the Mount of Olives after the rapture, is that they both involve his return! Look, I just used the word "return" to describe both events. Other words are used because there are similarities between the two events. This does not mean there is one event. Even the word "event" can be used to describe both occasions or events. Here are some other comparisons:
Both involve a descent of Christ.
Both involve his appearing.
Both involve his return.
Both involve him bringing Saints with him.
Both involve a trumpet blast.
Now the differences:
Pretrib: he descends only so far as into the air and then returns. John
14:1-4. 1 Thess 4.
Posttrib: he descends all the way to the earth and stays. Zech 14, Rev 19
Pretrib: he appears to the believers. Mat 5:8, John 11:40, Heb 9:28
Posttrib: he appears to everyone. Rev 1:7, Zech 12:10, Mat 24:30, Luke 3:6, John 19:37
Pretrib: he returns for the saints, to resurrect them to glory. 1 Thess
Posttrib: he returns with the resurrected and glorified saints. Rev 19
Pretrib: The last trump, at the Feast of Trumpets.
Posttrib: The great trump at the Day of Atonement.
There are many more differences, see: The Rapture vs. The Second Coming.
The parousia argument, "same word, same event" is an assumption. A groundless one at that.