The Collaborative International Dictionary of English v.0.48:

Handmaid \Hand"maid`\ (h[a^]nd"m[=a]d`), Handmaiden
\Hand"maid`en\ (h[a^]nd"m[=a]d`'n), n.
   A maid that waits at hand; a female servant or attendant.
   [WordNet sense 2]
   [1913 Webster]

   2. Something or someone serving in a subordinate position;
      as, theology should be the handmaiden of ethics. [WordNet
      sense 1]

   Syn: handmaid, servant.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

handmaid
    n 1: in a subordinate position; "theology should be the
         handmaiden of ethics"; "the state cannot be a servant of
         the church" [syn: handmaid, handmaiden, servant]
    2: a personal maid or female attendant [syn: handmaid,
       handmaiden]

Moby Thesaurus II by Grady Ward, 1.0:

67 Moby Thesaurus words for "handmaid":
   Charlie McCarthy, abigail, agent, amah, ancilla, appliance,
   au pair girl, ayah, betweenmaid, biddy, chambermaid, chaperon,
   companion, contrivance, cook, creature, device, duenna, dummy,
   dupe, femme de chambre, fille de chambre, gentlewoman, girl,
   go-between, handmaiden, hired girl, housemaid, implement,
   instrument, interagent, intermediary, intermediate, intermedium,
   kitchenmaid, lady-help, lady-in-waiting, lever, live-in maid,
   live-out maid, maid, maidservant, mechanism, mediator, medium,
   midwife, minion, nursemaid, organ, parlormaid, pawn, plaything,
   puppet, scullery maid, servant, servant girl, servitress, slave,
   soubrette, stooge, tool, toy, tweeny, upstairs maid, vehicle,
   waiting maid, wench



Easton's 1897 Bible Dictionary:

Handmaid
   servant (Gen. 16:1; Ruth 3:9; Luke 1:48). It is probable that
   Hagar was Sarah's personal attendant while she was in the house
   of Pharaoh, and was among those maid-servants whom Abram had
   brought from Egypt.