Hi Dimitri, I'll try to address all the topics.
It seems that "borda" is pretty popular in various translations of graphic layout, word processing, etc., applications, in settings where it means what "Border" means in the DialogEditStyleCtlTabBorder tag, for example, in Style and Layout contexts in Manifold.
LibreOffice in Brazilian Portuguese, for example, has many uses like:
Não confunda a borda do quadro com os limites do texto que podem ser visualizados usando o menu Exibir
That's a tough example Dimitri, I can assure you that in portuguese language we don't use that word in this context. In the previous example I believe "moldura" (that can literally be translated also as frame) or "contorno" are better words for the purpose (of course "borda" can also have this meaning, but it's just a really far-fetched term for this purpose). I'll not advise the use of borda in this context.
This line of thought also applies to the following example:
I think "grade" was used because programming/DBMS jargon seems to use "grade" for "grid", at least in some prominent settings. For example, if you look at the Visual Studio documentation in Portuguese, you see that Microsoft translates "Data Grid View" as "Exibição em Grade de Dados." Microsoft, of course, makes mistakes from time to time, but given that they have a lot of influence on technical people in Windows, if you use "grade" then programmers and DBMS people will know you mean "grid" in the sense that Manifold uses it, a row/column display.Does that seem reasonable?
It is reasonable, and most portuguese speakers will understand what you mean, but, again, it's just a possible translation and I believe a more common one in brazilian portuguese (more on this subject later). For me it's definitely not an "easy" term in this context.
I think "clip" or "Clip" occur in settings such as...
BuilderFunctionGeomClip=GeomClip(<geom>, <clip>, <inner>, <tolerance>) : <geom>
TemplateGeomClip=Clip Individual|Geom:|Clip with:|Tolerance:|Keep inner part
The meaning is different in the two cases although the same English word is used in both . In the first case, "clip" is used as "the cutter" or "the cutting instrument" so "lâmina" was used. In the second case, "clip" is used as a verb, "to cut", where "Cortar com" is good for "Clip with." What do you think of using a noun, perhaps "<cortador>" for similarity with the verb, to translate "<clip>"?
"Cortar com" is a good option for "Clip with", but "cortador" (I believe you refer to the transform operation that appears under the transform pane) just doesn't work (in portuguese "cortador" can mean both "cutting machine" or the "person who cuts meat in a butchery"). In my transform pane where Cortador and Cortador individual appears I would simply replace them with "Corte" and "Corte individual".
In the previous ui.file I mantained the "Label" translation as "Rótulo" (in fact, QGIS uses this terminology) but it seems that "Etiqueta" (like used in ArcGIS) should be a better fit. "Rótulo" can have a more specific portuguese meaning in GIS/CAD layouts, namely refering to the area in the page where you state the specs for the drawing (title, scale, author, owner, developer, ect.). In this line of thougth I believe "etiqueta" is a better translation for "label".
I would also advise to adopt "Intersetar" as the translation for Intersect (it's a literal and better translation than "cruzar" or "cruzando").
I noticed there is also a translation for Median Polish (that by now you can guess was translated as a median citizen of Poland) and I believe you're refering to Tukey's Median, refered in portuguese as "Mediana de Tukey". Is this assumption correct?
As for "Installed with mismatching options" I suggest "Instalado com opções incompatíveis", the present "Instalado com opções que não corresponde" doesn't have a very defined meaning.
In another expression, indeed "teto" means ceiling , but that not translates into something understandable. Do you think it's possible to sum up the "Ceiling up to Decimals" meaning by "Arredondar para cima até às décimas" or even by "Arredondar para valor superior até às décimas" (something like "Rounding to superior value to one decimal place")?
Overall, it seems that the original translation file was based in Brazilian Portuguese, and I can understand the confusion, since Portuguese and Brazilian portuguese are very similar indeed, but they are not the same language, that's why you have the following two libre office versions: Portuguese (Brazil) and português (Brasil) (usually abreviated by Pt-Pt and Pt-Br, or something similar). I believe it can be similar to what happens between En-US and En-UK.
As for further clarification, I'm using the "Acordo Ortográfico da Língua Portuguesa, 1990" (something like Portuguese Spelling Agreement adopted since 2009 and that can be mentioned by AO90). If you have the time to invest in this particular mess, I'll advise the reading of the following link: http://www.portaldalinguaportuguesa.org/acordo.php. Basically, there was an attempt by the portuguese "authorities" to "normalize" the portuguese language across all the different portuguese speaking contries. Official agreements were made between all countries involved, but in the end, besides Portugal, no other country adopted the agreement, ending up with extreme resistance and struggle to implement the agreement in Portugal (our language was previously defined by the Portuguese Spelling Agreement of 1945). Nowadays, the 1990 agreement is more accepted within Portugal (given that over the last 10 years the new generations were teached to write this way in elementary school) and all oficial documentation has to be written with AO90).
In the attached file I corrected a few more words (with accents): Hiperbólico; Círculo; Décima; Médio; Intermédio; Níveis; Divisões; elipsóide.