Created attachment 112908 [details]
average_dialog_label_naming.png

In LibreOffice Calc 4.3.5.2 on Windows 7:

1. Open Calc.
2. Type in values in cells:
   Cell A1: Product
   Cell A2: Product_A
   Cell A3: Product_B
   Cell B1: Price
   Cell B2: 100
   Cell B3: 150
3. With mouse select cells A1:B3.
4. Menu Data | Pivot Table | Create.
5. Select Source dialog open, just accept default and click OK button.
6. Pivot Table Layout dialog opens. From Available Fields move Product to Row Fields.
7. From Available Fields move Price to Data Fields.
5. In Data Fields member "Sum - Price" appears. Double click on this member. 
6. Data Field dialog opens. From Function selection select Average and click on OK button.
7. Now problem appears! In Pivot Table Layout dialog in Data Fields it appears: "Mean - Price". Instead of "Mean" I expect to get "Average" displayed, because I have selected Average. I know technically speaking Mean is perfectly fine word, but Average is what I expect to get.
8. Click on OK button to close Pivot Table Layout dialog.
9. New sheet opens with data. See the B1 data field "Average - Price". So this is additional confusion...

In step 6 there is word "Average", in step 7 it is word "Mean" in step 9 it is "Average" again. Confusing...

I think it should be the same word in all of the steps. I prefer word Average.

What is expected?
In step 7 instead of "Mean - Price" it should be "Average - Price".

See print-screen for clear picture.