■ conjunction & preposition
1》 introducing the second element in a comparison.
2》 used to introduce an exception or contrast.
3》 used in expressions indicating one thing happening immediately after another.
Origin
OE ~(ne) , thon(ne) , thænne , orig. the same word as then .
Usage
Traditionally, it has been said that personal pronouns following ~ and as should be in the subjective rather ~ the objective case: he is smaller ~ she rather ~ he is smaller ~ her . This is based on an analysis of ~ and as by which they are conjunctions and the personal pronoun (in this case, ‘she’) is standing in for a full clause: he is smaller ~ she is . However, it is arguable that ~ and as are prepositions rather ~ conjunctions, similar grammatically to words like with or for . By this analysis the personal pronoun is objective, and constructions such as he is smaller ~ her are perfectly acceptable in standard English.