外

そと · と

1. noun outside; exterior
2. the open (air)
3. other place; somewhere else; outside one's group (family, company, etc.)

ほか also 他

1. noun another place; some other place; somewhere else; outside
2. noun, takes の another (person or thing); other; different; something else; someone else; the rest; et al.
3. usually in kana, esp. 外 beyond (one's expectations, imagination, etc.); outside
4. noun, with neg. sentence; as ...ほかに...ない, ...するほかない, etc. except; but; other than; apart from
5. noun, adverb, as ...のほか（に）, ...するほか（に）etc. besides; in addition to; as well as; on top of

よそ also 余所 · 他所

1. noun, takes の, usually in kana another place; somewhere else; strange parts
2. usually in kana outside (one's family or group); someone else; other people
3. noun, usually in kana, as 〜をよそに, 〜をよそにして, etc. not caring for; being indifferent to; taking little notice of; ignoring; neglecting

がい

1. suffix outside ...; beyond ...; not included in ...