hǽlu

Part of speech: noun
Gender: feminine
Stem: -īn/ō-
1. safety; 2. health; 3. salvation (also hǽlo)
Etymology
[← Prot-Germ *hailīn (← *hailaz a + *-īn suff); O Sax hēli; OHG heilī (Mod G Heil “wellbeing, good; salvation”)]
Paradigm

1.1.2. (d) -īn/ō- stem

(subtype of -ō- stem nouns)

feminine gender

Abstract nouns derived from adjectives. strenȝ- (< *strangīn-; cf a stranȝ (strong)).

nouns, īn-/-ō- stem, feminine gender
strenȝu
(strength)
singular plural
nominative strenȝu, strenȝo strenȝa, strenȝe, strenȝu, strenȝo
genitive strenȝe, strenȝu, strenȝo strenȝa
dative (instrumental) strenȝe, strenȝu, strenȝo strenȝum
accusative strenȝe, strenȝu, strenȝo strenȝa

As seen from the above table, in the nouns belonging to this type (-īn/ō-), endings of the Nom case were spreading by analogy to other cases (except for Gen and Dat pl), resulting in the gradual transition of the nouns of this type virtually into the category of indeclinable words already in the OE period.