What does the ‘x’ in the extensions aspx, docx, xlsx, etc. represent?

calendar_today Asked Dec 6, 2010
thumb_up 11 upvotes
history Updated April 14, 2026

Direct Answer

For .aspx I assumed it stands for: Active Server Page eXtended format Though another opinion is that: these files typically contain static (X)HTML markup, as well as markup…. This is an advisory response with reference links, ranked #53rd of 95 by community upvote score, from 2010.


The Problem (Q-score 4, ranked #53rd of 95 in the VBA Core archive)

The scenario as originally posted in 2010

Or at least describe about.aspx

Why community consensus is tight on this one

Across 95 VBA Core entries in the archive, the accepted answer here holds solid answer (above median) status — meaning voters are unusually aligned on the right fix.


The Verified Solution — solid answer (above median) (+11)

Advisory answer — community consensus with reference links

Note: the verified answer below is a reference / advisory response rather than a copy-ready snippet.

For .aspx I assumed it stands for:

Active Server Page eXtended format

Though another opinion is that:

these files typically contain static (X)HTML markup, as well as markup defining server-side Web Controls and User Controls

Apparently it was the cool thing to do at time (the quote actually talks about the original name XSP, but doesn’t rule it out as an option):

The initial prototype was called “XSP”; Guthrie explained in a 2007 interview that, “People would always ask what the X stood for. At the time it really didn’t stand for anything. XML started with that; XSLT started with that. Everything cool seemed to start with an X, so that’s what we originally named it.”

For the office documents, since they are in XML format, it stands for XML.


When to Use It — vintage (14+ years old, pre-2013)

Ranked #53rd in its category — specialized fit

This pattern sits in the 91% tail relative to the top answer. Reach for it when your scenario closely matches the question title; otherwise browse the VBA Core archive for a higher-consensus alternative.

What changed between 2010 and 2026

The answer is 16 years old. The VBA Core object model has been stable across Office 2013, 2016, 2019, 2021, 365, and 2024/2026 LTSC, so the pattern still compiles. Changes that might affect you: 64-bit API declarations (use PtrSafe), blocked macros in downloaded files (Mark-of-the-Web), and the shift toward Office Scripts for web-first workflows.

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Frequently Asked Questions

Is this above-median answer still worth copying?
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Answer score +11 vs the VBA Core archive median ~4; this entry is solid. The score plus 4 supporting upvotes on the question itself (+4) means the asker and 10 subsequent voters all validated the approach.

This answer links out — what are the reference links worth following?
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Read the first external link for the canonical reference, then search this archive for a top-10 entry in the same category — advisory answers are best paired with a ranked code snippet to close the loop.

This answer is 16 years old. Is it still relevant in 2026?
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Published 2010, which is 16 year(s) before today’s Office 2026 build. The VBA Core object model has had no breaking changes in that window. Three things to re-test: (1) blocked macros on downloaded files (Mark-of-the-Web), (2) 64-bit API declarations (PtrSafe, LongPtr), (3) any shift toward Office Scripts for web scenarios.

Which VBA Core pattern ranks just above this one at #52?
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The pattern one rank above is “Problems with office automation in asp.net. I can use alternatives such as open-office, if I knew how”. If your use case overlaps, compare both before committing.

Data source: Community-verified Q&A snapshot. Q-score 4, Answer-score 11, original post 2010, ranked #53rd of 95 in the VBA Core archive. Last regenerated April 14, 2026.