Modifiers matching iron:

• organic,
• tough,
• metal,
• solid,
• soft,
• magnetic,
• special,
• virgin,
• liquid,

Simple categories matching solid:

• insulator,
• wax,
• material,
• foundation,
• object,
• metal,
• wood,
• color,
• waste,
• aerosol,
• growth,
• symbol,
• surface,
• medicament,
• refrigerant,
• fiber,
• catalyst,
• structure,
• fence,
• shape,
• fuel,
• line,
• acid,
• device,
• gemstone,
• stain,
• substrate,
• carbon,
• coal,
• paper,
• image,
• particle,
• investment,
• mixture,
• explosive,
• content,
• preparation,
• crystal,
• facility,
• block,
• product,
• mechanics,
• chemical,
• information,
• rest,
• space,
• fat,
• sphere,
• member,
• commodity,
• agent,
• anchor,
• particulate,
• evidence,
• cosmetic,
• absorbent,
• cylinder,
• fruit,
• cancer,
• ball,
• plant,
• malignancy,
• assets,
• core,
• cargo,
• fabric,
• characteristic,
• publication,
• carbonate,
• byproduct,
• sterol,
• base,
• volatile,
• hydrocarbon,
• science,
• entity,
• obstruction,
• mass,
• alcohol,
• missile,
• thing,
• board,
• abrasive,
• resin,
• deposit,
• impurity,
• solute,
• projectile,
• food,
• dielectric,
• grain,
• grey,
• region,
• obstacle,
• ingredient,
• hardwood,
• carrier,
• foam,
• projection,
• container,
• system,
• implement,
• contamination,
• sorbent,
• formation,
• fixture,
• section,
• interface,
• needle,
• lipid,
• value,
• rod,
• starches,
• salt,
• lead,
• earth,
• combustible,
• thread,
• dosage,
• unit,
• substratum,
• binder,
• fertilizer,
• meal,
• pollution,
• conductor,
• volume,
• topper,
• magnet,
• lesion,
• addition,
• joint,
• precursor,
• planet,
• coat,
• boundary,
• quality,
• tissue,
• platform,
• cheese,
• feed,
• ware,
• ballast,
• sweetener,
• data,
• adhesive,
• tree,
• makeup,
• cement,
• fencing,
• furniture,
• weapon,
• layer,
• tumor,
• idea,
• fertiliser,
• process,
• recovery,
• plan,
• substance,
• piece,
• laser,
• foodstuff,
• saccharide,
• body,
• manure,
• medium,
• tone,
• powder,
• carbohydrate,
• polymer,
• viscera,
• property,
• nature,
• shaft,
• aluminum,
• wall,
• film,
• residue,
• sample,
• tool,
• form,
• protein,
• ink,
• propellant,
• beverage,
• hair,
• timber,
• profession,
• filler,
• attribute,
• team,
• figure,
• rock,
• part,
• mineral,
• oil,
• soil,
• nickel,
• subject,
• support,
• area,
• stuff,
• sheet,
• bar,
• fastener,
• organ,
• coating,
• world,
• ornament,
• organs,
• converter,
• drink,
• debris,
• favorite,
• feature,
• electrode,
• message,
• contaminant,
• barrier,
• decoration,
• neoplasm,
• polygon,
• recipe,
• edible,
• pin,
• composition,
• stone,
• component,
• matter,
• footwear,
• concrete,
• pane,
• element,
• plastic,
• ring,
• iron,
• fluid,
• pollutant,
• specimen,
• stick,
• colors,
• state,
• footgear,
• medication,
• backing,
• instrument,
• fare,
• flooring,
• brand,
• counter,
• construction,
• electrolyte,
• spread,
• portion,
• credential,
• clothing,
• tumour,
• equipment,
• receptacle,
• medicine,
• oxide,
• drug,
• aggregate,
• matrix,
• embolus,
• top,
• constituent,
• education,
• deformation,
• thermoplastic,
• biomass,
• article,
• sugar,
• item,
• guidebook,
• scrap,
• vegetable,
• compound,
• representation,
• fibre,
• lubricant,
• slurry,