Welding glossary: terms in ten languages with EN ISO designations

The terms that come up in a WPS, on a drawing and in the workshop, in ten languages side by side. Type in the search box to filter — it searches all ten columns at once.

Nothing found. Try another word, or browse the sections instead.

Print this table

Three traps worth knowing

Imperfection versus defect. In ISO 5817 an imperfection is any deviation from the ideal weld, and it becomes a defect only when it exceeds the limit for the quality level. Inspectors use the words precisely; site conversation does not. See the defect catalogue.

Throat and leg. English uses "throat thickness" for the dimension a and "leg length" for z. Reading a5 as a 5 mm leg produces a weld a third smaller than the drawing asked for — the conversion is in the fillet weld calculator.

Heat input versus arc energy. Arc energy is U · I / v; heat input is arc energy multiplied by the thermal efficiency of the process. Documents distinguish them and the numbers differ by up to 40 % (k = 0.6 for TIG, 0.8 for MMA and MAG). See the heat input calculator.

How to search so you find it

• Type the stem, not the whole word. “weld” finds welding, welding fume and welder qualification at once.
• Search in whatever language you know. The filter runs over every column, so you can type fillet, Polish pachwinowa or Russian «угловой» — and land on the same row.
• Several words narrow it down. “fillet weld” shows only rows containing both words, in any order.
• Abbreviations work too. WPS, VT, MMA and TIG appear in the entries, so an abbreviation from a drawing or report gives the full name straight away.
• Diacritics count. “gran” will not find Polish grań. If a foreign word does not turn up, search the English term — the translation is in the same row.

Terms by topic, and where to read more

The glossary is split into the same groups as the table above. Each group has example terms and the pages on this site where those ideas are covered in practice.

Working in Poland with this glossary

The Polish column is here for a reason: drawings, WPS and inspection reports on Polish sites are in Polish, and the crews are mixed. Before the first job it is worth knowing a handful of words that turn up on every WPS — energia liniowa (heat input), podgrzewanie wstępne (preheating), temperatura międzyściegowa (interpass temperature). How welder certificates are recognised there is covered in welding qualifications in Poland, and the paperwork for foreign workers in working as a foreign welder.

The glossary on site: three situations

• Briefing at the drawing. The foreman says grań, the welder looks it up and sees “weld root”; the symbols themselves are read using welding drawing basics.
• An inspection report. The Polish VT report says podtopienie, the English appendix says undercut — one term, one row.
• Ordering materials. Shielding gas is gaz osłonowy in Polish and Schutzgas in German — handy with a foreign supplier.

Author: Dmitry Frolov, welder and metal fabricator Updated: 24 October 2026