../parent

typedef

Start looking for values in the parent context.

`../key`

Look for values starting in the parent context.

{{#each todos}}
    <div class='{{#if ../isEditing(this)}}editing{{/if}}'>
        {{./name}}
    </div>
{{/each}}

Adding ../ before a key will lookup the key starting in the parent context. By changing the previous template to:

{{first}} {{last}}
  {{#children}}
    {{first}} {{../last}}
  {{/children}}

It will write out:

Barry Meyer
    Kim Meyer
    Justin Meyer

You can use .././last to lookup last only in the parent context.