# [Label] on a field: what a report calls it, in the reader's language

> Where the platform names a field itself (a report's field picker, a column heading, a filter read back as a sentence), it says the field's `[Label("…")]`, or its name in words when it has none (`ArrivedAt` is "Arrived at"). Both are texts, exactly like an enum member's label: `osy translate` extracts them, and a reader sees them in their own language.

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## Summary        {#summary}
A field's name is code; what a person reads for it is a word. Give the word with `[Label]`:

```osy syntax
entity Parcel {
  [Label("Weight (kg)")] decimal Kilos;   // a report says "Weight (kg)"
  DateTime ArrivedAt;                     // a report says "Arrived at"
}
```

`osy translate` lists both in the locale files, and a Swedish reader's field picker says "Vikt (kg)" and "Inkom".

## Signature      {#signature}
```osy syntax
[Label("<the words a person reads>")] <type> <Name>;   // on an entity field
```

## Description    {#description}

### When does a field's name need a label?   {#when}
When its name in words is not what your readers call it. `ArrivedAt` reads well as "Arrived at" and needs nothing;
`Kilos` is better as "Weight (kg)", and `Form` as "Type". The label replaces the name wherever the platform names the
field. Your own pages are untouched: a form's `TextField("Weight", …)` says what you wrote there.

### Which field names are translated?   {#extracted}
Every declared `[Label]`, and the name in words of every field a report's field picker can reach: the fields of each
entity a report starts from (`Explore.Root<Parcel>()`), and of the entities three steps away through its references
and collections, their bases' fields included, plus "Created at" and "Modified at", which every stored entity has.
A field nothing reports on keeps its name to itself, so the locale files list only words somebody can read.

A field's words share one translation with every other label of the same words: a field called "Status" and an enum
member labelled "Status" are one entry. Read on the server, in the language of the request (or the one
`Session.SetLanguage` chose), so a field picker, its column headings and a filter's sentence all follow the reader.

### Where a kit's fields are translated   {#kits}
A kit's field is in the kit's locale file (`sv.Osysharp.WorkQueues.osy`), as its enum labels are, so an app that reports
on a kit's entity translates the kit's field names once, beside the kit's other words.

## Examples       {#examples}

### A field with a label, and one read by its name   {#example-parcel}
```osy title="a label on a field, and the field picker that says it" test app=i18n-field-labels
using Osysharp.Explore;

entity Courier { [Required, MaxLength(80)] string Name; }

entity Parcel {
  [Label("Weight (kg)")] decimal Kilos;
  DateTime ArrivedAt;
  Courier? Courier;
  security { allow read when IsAuthenticated; }
}

/// What the field picker offers for a parcel: "Weight (kg)", "Arrived at", "Courier", "Courier › Name" …
List<string> ParcelFieldWords() {
  return Explore.Fields(Explore.Root<Parcel>(), 2).Select(f => f.Label).ToList();
}
```

## See also       {#see-also}
- [Which words are translated — the compiler finds every text a reader sees](https://osysharp.com/reference/i18n/extraction/) — every other word the compiler finds
- [osy translate — the request for any model, and its answer read back](https://osysharp.com/reference/i18n/translate/) — `osy translate`, which writes these into the locale files
- [The Reports kit — reports a team builds, and the overview it opens every morning](https://osysharp.com/reference/ui/reports-kit/) — the field picker, the column headings and the filters that say them